CVE-2026-5089
YAML::Syck versions before 1.38 for Perl has an out-of-bounds read
- Published
- Updated
- Reserved
- Assigned by
- CPANSec
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High7.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L |
| NVDNVD · Deferred | 3.1 | High7.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L |
- EPSS (exploitation in 30 days)
- 0.40% · top 65% of all CVEs (5 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.3.
Weakness
Affected products
- affected < 1.38
What to do
Solution: Upgrade to YAML::Syck version 1.38 or later.
References (5)
- https://metacpan.org/release/TODDR/YAML-Syck-1.38/changes (opens in a new tab)release-notes
- https://github.com/cpan-authors/YAML-Syck/issues/132 (opens in a new tab)issue-trackingexploit
- https://github.com/cpan-authors/YAML-Syck/pull/133 (opens in a new tab)issue-tracking
- https://github.com/cpan-authors/YAML-Syck/commit/208a4d3bd1b5cdb4a791a6e3905bd6bd45e9d005.patch (opens in a new tab)patch
- http://www.openwall.com/lists/oss-security/2026/05/12/16 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-5089)Record last updated .