chore(deps): update dependency pillow to v12.3.0 [security] - #86
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Coverage Report for CI Build 30156698620Coverage remained the same at 27.981%Details
Uncovered ChangesNo uncovered changes found. Coverage RegressionsNo coverage regressions found. Coverage Stats
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This PR contains the following updates:
==12.2.0→==12.3.0Pillow EpsImagePlugin negative %%BeginBinary byte count causes infinite loop denial of service
CVE-2026-59203 / GHSA-pg7v-jwj7-p798
More information
Details
Summary
Pillow's EPS parser (PIL/EpsImagePlugin.py) accepts a negative byte count in the %%BeginBinary directive. A crafted EPS file can cause Image.open() to seek backwards to the same directive and parse it repeatedly, resulting in an infinite loop and CPU denial of service.
The issue is triggered during Image.open(), does not require Image.load(), and does not require Ghostscript execution.
Confirmed affected versions: Pillow 12.0.0 through 12.2.0.
Details
The issue is in the EPS parser in PIL/EpsImagePlugin.py. When parsing an EPS %%BeginBinary directive, Pillow reads the byte count from the file and passes it directly to a relative seek operation without validating that the value is non-negative.
Relevant code:
There is no validation that bytecount is non-negative.
If an attacker provides a negative value such as %%BeginBinary:-18, the parser moves the file pointer backwards from the end of the directive line to the same line region. The next parser iteration reads the same %%BeginBinary:-18 directive again, performs the same backward seek, and repeats indefinitely. This causes Image.open() to hang in an infinite loop and consume CPU.
In local testing, the issue is present in Pillow 12.0.0, 12.1.0, 12.1.1, and 12.2.0. Pillow 11.3.0 did not hang with the same PoC, so this appears to affect the 12.x EPS parsing path.
PoC
Save the following content as pillow_eps_beginbinary_dos.eps:
Then run:
Expected behavior: Pillow should reject the malformed EPS file with a parser exception.
Actual behavior: the process does not return. It hangs inside Image.open() and continuously consumes CPU.
The loop behavior can be observed by tracing the parser state. The file pointer repeatedly seeks from position 112 back to 94, causing the same %%BeginBinary:-18 line to be parsed again and again:
Impact
This is a denial-of-service vulnerability. An attacker who can provide an EPS file to an application using Pillow for image validation, metadata parsing, previews, uploads, or batch image processing can cause the image parsing process to hang during Image.open().
This can impact web services and backend workers that parse untrusted image files, especially if image parsing is performed in a main worker process without CPU limits, timeouts, or process isolation. The issue does not require Ghostscript execution and does not require calling Image.load(), so applications that only use Image.open() to validate or identify uploaded images may still be affected.
Suggested fix: validate the parsed %%BeginBinary byte count before seeking. If the byte count is negative, reject the file with a parsing exception instead of calling self.fp.seek(bytecount, os.SEEK_CUR).
Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow: Out-of-bounds read via attacker-controlled row stride on Pillow's mmap path (McIdas AREA files)
CVE-2026-54058 / GHSA-62p4-gmf7-7g93
More information
Details
Summary
When Pillow loads an uncompressed image whose tile uses the
rawcodec and a mode inImage._MAPMODES, and the image was opened from a filename, it memory-maps the file and builds the image's row pointers directly into the mapping viaPyImaging_MapBuffer(src/map.c). The per-row spacing (stride) is taken from the tile arguments.map.cvalidatesoffset + ysize*stride <= buffer_lenbut never checks thatstrideis at least the natural row widthxsize * pixelsize.The McIdas AREA plugin (
McIdasImagePlugin.py) derivesstride,offset,xsize, andysizedirectly from attacker-controlled 32-bit header words with no validation. By supplying astridefar smaller than the row width, an attacker makes each row pointer readxsize*pixelsizebytes that run past the mapped region. Accessing the pixels (e.g.Image.tobytes(),getpixel,convert,save) then reads adjacent process memory (information disclosure) or faults (SIGBUS, denial of service).Complete Code Trace
Step 1:
McIdasImageFile._open- turns attacker header words into image size, file offset, and row stride with no validation.Step 2:
ImageFile.load(mmap branch) - selects mmap and delegates tomap_buffer.Step 3:
PyImaging_MapBuffer- builds row pointers atstridespacing into the mmap; validates everything exceptstride >= row width.im->linesize(the number of bytes any consumer reads per row) isxsize * pixelsize = 200000, but the row pointers are onlystride = 1byte apart and the buffer is onlyoffset + ysize*stride = 2bytes "claimed". Nothing reconciles the two.Step 4: pixel access (
Image.tobytes()→ raw encodercopy1) - readslinesizebytes fromim->image[0], i.e.xsizebytes starting atview.buf + offset, running far past the mmap.Chain Summary
Proof of Concept
See attached poc.zip
Impact on a Parent Application
Any application that opens image files supplied by users from a path on disk (the common pattern: save upload to a temp file, then
Image.open(path)), has the default plugin set (McIdas is registered by default), and subsequently reads/returns/re-encodes the decoded pixels (thumbnailing, format conversion, serving a preview), is exposed:xsizereliably crashes the worker with SIGBUS.Suggested fix
Core fix in
src/map.c(PyImaging_MapBuffer): rejectoffset < 0andstride < im->linesize. Defense-in-depth inMcIdasImagePlugin._open: rejectoffset < 0orstride < xsize*pixelsize.Severity
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:NReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow:
FontFile.compile():Image.new()called without_decompression_bomb_check()CVE-2026-54060 / GHSA-5x94-69rx-g8h2
More information
Details
Description
PIL/FontFile.pyFontFile.compile()assembles per-glyph images into a single combined bitmap usingImage.new("1", (xsize, ysize))without callingImage._decompression_bomb_check(). This is the base-class method shared by bothBdfFontFileandPcfFontFile, and it is triggered whenever a loaded font is converted to anImageFontor saved.Neither
BdfFontFile.BdfFontFile(fp)norPcfFontFile.PcfFontFile(fp)is registered withImage.register_open(), so Pillow's standard decompression bomb guard never fires for font objects. The compile step is the final opportunity to check the combined allocation — and it has no check.Vulnerable code (
PIL/FontFile.pylines ~64–92):"Slow accumulation" attack — per-glyph dimensions stay BELOW warning threshold:
With PCF-maximum glyph height (65,535):
Steps to reproduce
Proof of Concept script:
Expected output:
Verified live on Pillow 12.2.0 — compile() succeeds with no exception.
Real-world trigger using BDF font file:
Attack scenarios:
BdfFontFile(upload).to_imagefont())to_imagefont()Impact
compile()creates a combined bitmap whose pixel count scales asWIDTH × lines × max_glyph_heightwith no upper bound check. With max PCF glyph height (65,535) and 256 glyphs, the combined allocation is ~1.6 GB. With BDF (text-format, unbounded height), the allocation is limited only by system memory.Affected call paths:
BdfFontFile.BdfFontFile(fp).to_imagefont()→FontFile.compile()BdfFontFile.BdfFontFile(fp).save(filename)→FontFile.compile()PcfFontFile.PcfFontFile(fp).to_imagefont()→FontFile.compile()PcfFontFile.PcfFontFile(fp).save(filename)→FontFile.compile()Neither
BdfFontFilenorPcfFontFileis loaded viaImage.open(), so the standard decompression bomb guard is entirely absent from the font loading code path.compile()is the only point where the combined allocation size is known, and it has no check.Confirmed unpatched on
python-pillow/Pillowmainbranch as of 2026-06-08.Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow
PcfFontFile._load_bitmaps():Image.frombytes()called without_decompression_bomb_check()— bomb protection bypass via PCF font loadingCVE-2026-54059 / GHSA-8v84-f9pq-wr9x
More information
Details
Description
PIL/PcfFontFile.py_load_bitmaps()(line 227) reads glyph dimensions from the PCFMETRICSsection and passes them directly toImage.frombytes()without callingImage._decompression_bomb_check(). Dimensions originate from unsigned 16-bit values:Maximum exploitable pixel count: 65,535 × 131,070 = 8,589,734,450 pixels — 48× the DecompressionBombError threshold.
Vulnerable code (
PIL/PcfFontFile.pyline 224–227):Image.frombytes()callsImage.new()first (allocating the full C-heap buffer), then attempts to fill it. This creates two distinct attack paths:frombytes()succeeds → image stored infont.glyph[ch]permanentlyImage.new()allocates the full buffer →ValueError→ buffer freed → but the spike occurs before Python can respondSteps to reproduce
Proof of Concept script:
Expected output:
Amplification table:
Impact
PcfFontFile(fp)) is affectedPcfFontFileis never loaded viaImage.open(), so the bomb check protection is completely absent from the entire PCF font loading pathpython-pillow/Pillowmainbranch as of 2026-06-07Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow
BdfFontFile:Image.new()called without_decompression_bomb_check()— bomb protection bypass via font loadingCVE-2026-55379 / GHSA-45hq-cxwh-f6vc
More information
Details
Summary
PIL/BdfFontFile.pybdf_char()(lines 84–88) reads theBBX width heightfield from a BDF font file and passes the dimensions directly toImage.new()without callingImage._decompression_bomb_check(). This completely bypasses Pillow's documented decompression bomb protection.Image.open()enforcesMAX_IMAGE_PIXELS = 89,478,485and raisesDecompressionBombErrorfor images exceeding2 × MAX = 178,956,970pixels. The BDF font loading path callsImage.new()directly, which only calls_check_size()(validates>= 0) — no pixel count limit.Vulnerable code (
PIL/BdfFontFile.pylines 84–88):Attack trigger: A BDF glyph with
BBX 20000 20000and an emptyBITMAPsection causesImage.frombytes()to raiseValueError, thenImage.new("1", (20000, 20000))allocates 50 MB of C-heap silently. Image.open() would raiseDecompressionBombErrorfor the same dimensions.Steps to reproduce
Minimal malicious BDF file (270 bytes):
Proof of Concept script:
Expected output:
Amplified attack (multiple glyphs):
A BDF file defining 256 glyphs each at
BBX 8000 8000causes256 × 7.6 MB = ~1.95 GBtotal C-heap allocation — all silently, bypassing documented bomb protection.Impact
ImageFont.load("user.bdf"),BdfFontFile(fp)) is affectedself.glyph[ch]for the lifetime of the font object — memory is NOT freed until the font is garbage collectedSeverity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow
GdImageFile._open(): image dimensions accepted without_decompression_bomb_check()CVE-2026-55380 / GHSA-phj9-mv4w-65pm
More information
Details
Description
PIL/GdImageFile.pyGdImageFile._open()reads image dimensions from the GD 2.x header and stores them inself._sizewithout callingImage._decompression_bomb_check(). BecauseGdImageFileis not registered withImage.register_open(), it never passes through the standardImage.open()code path that enforces Pillow's decompression bomb guard. The plugin exposes its own entry point —PIL.GdImageFile.open(fp)— which directly instantiates the class, fully bypassing the documented protection.Vulnerable code (
PIL/GdImageFile.pylines 50–61):When
load()is subsequently called on the returned image object:Dimension arithmetic:
DecompressionBombErrorthresholdComparison with safe sibling plugin (
WalImageFile):WalImageFileis in the same category — not registered withImage.open(), loaded via its ownopen()helper. It was previously patched with the correct fix:GdImageFilewas never updated to match, leaving a gap in protection.Steps to reproduce
Proof of Concept script:
Expected output:
Verified live on Pillow 12.2.0.
Two attack paths:
load_prepare()attempts 4.3 GB C allocation →OSErrorafter spikeload()completes, 4.3 GB stays in memory for object lifetimeFor the transient path, a 1,037-byte file is all that is needed. The attacker does not need to upload a large file.
Real-world scenario:
Impact
.gdfile causes the host process to attempt a ~4.3 GB C-heap allocation. On systems with insufficient memory this crashes the process. Repeatable — attacker can loop requests to keep the server down.Any service that calls
PIL.GdImageFile.open(user_file)followed by.load()(or any lazy-load trigger) is vulnerable. Because the attack requires only a 1,037-byte file, network bandwidth is not a constraint.Confirmed unpatched on
python-pillow/Pillowmainbranch as of 2026-06-08.Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow: WindowsViewer.get_command() OS command injection via unescaped shell path
CVE-2026-55798 / GHSA-4x4j-2g7c-83w6
More information
Details
1. Summary
WindowsViewer.get_command()constructs acmd.exeshell command by directly embedding afile path into an f-string without escaping. The result is passed to
subprocess.Popen(..., shell=True). Shell metacharacters in the file path — mostimportantly a double-quote (
") that breaks out of the wrapping, followed by&— allowinjection of arbitrary
cmd.execommands.The macOS equivalent (
MacViewer) correctly appliesshlex.quote()to the same parameter.The Linux equivalent (
UnixViewer) does likewise. Windows is the only platform missing thisprotection, despite
shlex.quotebeing already imported on line 21 ofImageShow.py.2. Vulnerable Code
File:
src/PIL/ImageShow.py, lines 133–150Contrast with macOS — SAFE (line 164–168):
Cross-platform summary:
shlex.quote()?shell=True?MacViewerUnixViewerWindowsViewershlex.quoteis imported on line 21. Its omission from the Windows path is a clearoversight, not a deliberate design choice.
3. Proof of Concept
A full working PoC is at
poc_pillow_injection.py. Key parts:Part A — Injection string construction (static, no execution):
Part B — Live execution via
os.system()(verified on Windows 11, Pillow 12.1.1):Severity
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:LReferences
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Pillow: Heap out-of-bounds write
Image.paste()/Image.crop()via signed coordinate overflowCVE-2026-59199 / GHSA-6r8x-57c9-28j4
More information
Details
Summary
Pillow's public image coordinate APIs can trigger a native heap out-of-bounds
write when given coordinates near the signed 32-bit integer limits. In 4-byte
pixel modes such as
RGBA, this becomes a controlled backward heap underwrite:for a source image of width
W, Pillow writes4 * Wattacker-controlled bytesstarting
4 * Wbytes before the destination row pointer. With successful largeimage allocation, the theoretical upper bound is ~2 GiB backwards from
the destination row.
Minimal public API trigger:
The same root cause is also reachable through
Image.crop()andImage.alpha_composite(). No private API, ctypes, custom Python object, ormalformed image file is needed.
This has been confirmed as an ASAN heap-buffer-overflow write. On normal
non-ASAN Pillow builds, the minimal trigger corrupts the heap and aborts with
double free or corruption (out)Details
src/PIL/Image.py:paste()accepts a 4-tuple box and passes it to the nativeImagingCore.paste()method:src/_imaging.c:_paste()parses the four Python coordinates into signedintvalues and calls
ImagingPaste():src/libImaging/Paste.c:ImagingPaste()computes and clips the region usingsigned
intarithmetic:With
dx0 = 2147483646anddx1 = -2147483648,dx1 - dx0wraps to2.That matches the 2-pixel source image, so the size check passes. The later
dx0 + xsizeclip check wraps around and does not reject the out-of-boundsdestination.
For 4-byte pixel modes such as
RGBA, the paste loop then multipliesdxbypixelsize:For the minimal PoC, this writes 8 attacker-controlled bytes 8 bytes before the
destination row allocation.
The primitive scales with the attacker-controlled source width:
Examples for
RGBA:Pillow's image creation guard currently limits
xsizeto roughlyINT_MAX / 4 - 1, so the theoretical upper bound for thisRGBAunderwrite is2,147,483,640bytes before the destination row pointer. In practice, theusable range depends on memory availability, allocator layout, and process heap
state.
Two other documented APIs reach the same sink:
Image.crop()keepsright - leftsmall, so the Python decompression-bombcheck allows it.
src/libImaging/Crop.cthen computes wrapped pastecoordinates and calls
ImagingPaste().PoC
The following standalone script exercises all three public API paths. Save it
as
b021_poc.pyand run it withpaste,crop, oralpha.Run against an ASAN build:
Observed ASAN signature for the direct
Image.paste()path:On non-ASAN Pillow
12.2.0and local12.3.0.dev0, the direct minimalImage.paste()trigger returns frompaste()and then the process abortsduring cleanup with:
Observed ASAN signature for the
Image.crop()andImage.alpha_composite()paths:
Suggested fix
Avoid signed overflow in paste/crop coordinate arithmetic. Use checked
arithmetic or a wider type before calculating widths and clipped endpoints.
For example, reject boxes whose endpoint subtraction cannot be represented
cleanly, and clip using non-overflowing comparisons:
ImagingCrop()should receive the same treatment forsx1 - sx0,dx0 = -sx0, anddx1 = imIn->xsize - sx0.Impact
This is a heap out-of-bounds write in Pillow's native C extension, reachable
through documented public image APIs.
Applications are impacted if an untrusted user can control image operation
coordinates passed to Pillow, for example crop boxes, paste boxes, or overlay
positions. The bytes written in the direct
Image.paste()variant are copiedfrom the source image, so attacker-controlled source pixels can influence the
out-of-bounds write. For
RGBA, the write is a backward heap underwrite whoseoffset and length are both
4 * source_width, bounded in practice by successfulimage allocation and heap layout.
Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HReferences