CVE-2026-5089
Description
YAML::Syck versions before 1.38 for Perl has an out-of-bounds read. The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer: while ( colon >= ptr && *colon != ':' ) { colon--; } if ( *colon == ':' ) *colon = '\0'; // colon may be ptr-1 here When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | affected | |
| debian | bullseye | affected | |
| debian | forky | fixed | 1.36-3 |
| debian | sid | fixed | 1.36-3 |
| debian | trixie | affected | |
References
- https://github.com/cpan-authors/YAML-Syck/commit/208a4d3bd1b5cdb4a791a6e3905bd6bd45e9d005.patch
- https://github.com/cpan-authors/YAML-Syck/issues/132
- https://github.com/cpan-authors/YAML-Syck/pull/133
- https://metacpan.org/release/TODDR/YAML-Syck-1.38/changes
- http://www.openwall.com/lists/oss-security/2026/05/12/16
- https://security-tracker.debian.org/tracker/CVE-2026-5089
CWEs
CWE-124
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.