ClamAV 1.5.3 is a patch release with the following fixes:
- CVE-2026-20217:
Fixed a bug in the PESpin unpacker cleanup path that could free pointers
into the scanned file buffer and crash the scanner.
This issue affects ClamAV 1.5.2, 1.4.4, and all prior versions as far back
as 2005.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Atuin - Automated Vulnerability Discovery Engine, Tianchu Chen
of Tencent Xuanwu Lab for identifying this issue.
- CVE-2026-20213:
Fixed an integer overflow in PE rebuild size calculations that could be
reached through a malformed Aspack-packed PE file and lead to a heap buffer
overflow write.
This issue affects ClamAV 1.5.2, 1.4.4, and all prior versions as far back
as 2007.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Trail of Bits, in collaboration with Anthropic, for identifying
this issue.
- CVE-2026-20216:
Fixed an InstallShield archive extraction limit bypass that could write far
more temporary data than intended and exhaust temporary storage.
This issue affects ClamAV 1.5.2, 1.4.4, and all prior versions as far back
as 2009.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Mizu for identifying this issue.
- CVE-2026-20214:
Fixed an FSG unpacker loop underflow that could write past the section array
while scanning a malformed PE file.
This issue affects ClamAV 1.5.2, 1.4.4, and all prior versions as far back
as 2004.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Trail of Bits, in collaboration with Anthropic, for identifying
this issue.
- CVE-2026-20243:
Fixed ALZ parser size handling bugs that could cause malformed ALZ archives
to panic, abort the scanner, or skip expected scan-limit handling.
This issue affects ClamAV 1.5.0 through 1.5.2 and 1.4.0 through 1.4.4.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Yazdan Soltani for identifying this issue.
- CVE-2026-20215:
Fixed a 7z parser substream count overflow that could under-allocate parser
metadata arrays and write past them while reading a malformed archive.
This issue affects ClamAV 1.5.2, 1.4.4, and all prior versions back to 2009.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Trail of Bits, in collaboration with Anthropic, for identifying
this issue.
- CVE-2026-20244:
Fixed 32-bit DMG parser size checks that could let a short mish stripe table
pass validation and crash 32-bit scanner builds.
This issue affects 32-bit ClamAV builds from 0.98.1 through 1.5.2, including
1.4.0 through 1.4.4 and 1.5.0 through 1.5.2. It does not affect 64-bit
builds.
The fix is included in 1.5.3 and 1.4.5.
Thank you to Stanley John Tobias for identifying this issue.
- Hardened clamscan, clamdscan, and clamonacc quarantine actions against
time-of-check/time-of-use races that could redirect copied, moved, or removed
files under unsafe quarantine directory configurations.
Thank you to Hiroki Imai from Ricerca Security, Inc. for identifying this
issue.
- Upgraded the Rust tar dependency to resolve the RUSTSEC-2026-0067 and
RUSTSEC-2026-0068 advisories, and upgraded the Rust openssl dependency to
resolve CVE-2026-41676.
- Raised the minimum required CMake version to 3.17 to fix Linux builds with
libcurl v8.21.0 when linking static library dependencies.
- Metadata preclass scans now run before the final scan verdict.
- ClamOnAcc: Fixed errors when recursively excluded paths are children of an
included path.
- ClamOnAcc: Fixed hash bucket list corruption when two watched paths collide
in the same bucket.
These fixes are courtesy of sharkautarch.
