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Reading unbounded number of HTTP/2 CONTINUATION frames to cause excessive CPU usage

Moderate
tatsuhiro-t published GHSA-x6x3-gv8h-m57q Apr 4, 2024

Package

No package listed

Affected versions

< 1.61.0

Patched versions

1.61.0

Description

Impact

nghttp2 library keeps reading the unbounded number of HTTP/2 CONTINUATION frames even after a stream is reset to keep HPACK context in sync. This causes excessive CPU usage to decode HPACK stream.

See also https://www.kb.cert.org/vuls/id/421644

Patches

nghttp2 v1.61.0 mitigates this vulnerability by limiting the number of CONTINUATION frames it can accept after a HEADERS frame.

Workarounds

There is no workaround for this vulnerability.

References

The following commits mitigate this vulnerability:

The first commit limits the number of CONTINUATION frames after a HEADERS frame to 8.
The second commit makes the limit configurable.

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVE ID

CVE-2024-28182

Weaknesses

No CWEs