Fix use-after-free in ParsedConfigCache for short config strings#13078
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maskit merged 1 commit intoapache:masterfrom Apr 13, 2026
Merged
Fix use-after-free in ParsedConfigCache for short config strings#13078maskit merged 1 commit intoapache:masterfrom
maskit merged 1 commit intoapache:masterfrom
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- Fix use-after-free in ParsedConfigCache when config values are short enough for std::string SSO (Small String Optimization) - ParsedValue::parse() returned by value, and emplace moved it into the map — relocating the SSO inline buffer while string_views in TargetedCacheControlHeaders::headers[] still pointed to the old address - Make ParsedValue non-movable and use try_emplace + parse_into() so parsing happens directly in the map node - Also fixes the same class of bug for HostResData::conf_value and HttpStatusCodeList::conf_value pointers Reproducer: configure conf_remap with a short targeted header value like ACME-Cache-Control (18 chars, within libc++ SSO threshold of 22). The string_views in the per-transaction override become dangling, causing incorrect cache behavior. The SSO threshold varies by standard library — libc++ (macOS/clang): 22 bytes, libstdc++ (GCC/Linux): 15 bytes. A value like ACME-Cache-Control (18 chars) triggers SSO on libc++ but uses heap allocation on libstdc++, where the buffer pointer survives the move. This is why the bug may reproduce on macOS but not on Linux CI with GCC.
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Cherry-picked to 10.2.x |
cmcfarlen
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Apr 15, 2026
) - Fix use-after-free in ParsedConfigCache when config values are short enough for std::string SSO (Small String Optimization) - ParsedValue::parse() returned by value, and emplace moved it into the map — relocating the SSO inline buffer while string_views in TargetedCacheControlHeaders::headers[] still pointed to the old address - Make ParsedValue non-movable and use try_emplace + parse_into() so parsing happens directly in the map node - Also fixes the same class of bug for HostResData::conf_value and HttpStatusCodeList::conf_value pointers Reproducer: configure conf_remap with a short targeted header value like ACME-Cache-Control (18 chars, within libc++ SSO threshold of 22). The string_views in the per-transaction override become dangling, causing incorrect cache behavior. The SSO threshold varies by standard library — libc++ (macOS/clang): 22 bytes, libstdc++ (GCC/Linux): 15 bytes. A value like ACME-Cache-Control (18 chars) triggers SSO on libc++ but uses heap allocation on libstdc++, where the buffer pointer survives the move. This is why the bug may reproduce on macOS but not on Linux CI with GCC. (cherry picked from commit 4f97333)
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Reproducer: configure conf_remap with a short targeted header value like ACME-Cache-Control (18 chars, within libc++ SSO threshold of 22). The string_views in the per-transaction override become dangling, causing incorrect cache behavior.
The SSO threshold varies by standard library — libc++ (macOS/clang): 22 bytes, libstdc++ (GCC/Linux): 15 bytes. A value like ACME-Cache-Control (18 chars) triggers SSO on libc++ but uses heap allocation on libstdc++, where the buffer pointer survives the move. This is why the bug may reproduce on macOS but not on Linux CI with GCC.