CVE-2026-5089
Published: May 21, 2026Last modified: May 25, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.3 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | LOW |
| Integrity impact | LOW |
| Availability impact | LOW |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | perl-yaml-syck | Fixed (1.34-r4) |
| 25 LTS | perl-yaml-syck | Fixed (1.34-r7) | |
| Stream | perl-yaml-syck | Fixed (1.45-r0) |
References
- http://www.openwall.com/lists/oss-security/2026/05/12/16
- 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