CVE-2026-5089 YAML::Syck versions before 1.38 for Perl has an out-of-bounds read
An out-of-bounds read in YAML::Syck allows attackers to cause denial of service or disclose memory contents via crafted YAML input.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-5089?
CVE-2026-5089 is a high-severity memory corruption vulnerability in TODDR YAML::Syck, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-124
Which versions are affected by CVE-2026-5089?
Linux distribution packages (2)
perl-YAML-Syck openSUSE:Leap 16.0 | All versions | 1.450.0-bp160.2.1 |
perl-YAML-Syck openSUSE:Tumbleweed | All versions | 1.450.0-4.1 |
How do I fix CVE-2026-5089?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-5089 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5089 exists.
Sources
Also known as AZL-109511, AZL-86901, BELL-CVE-2026-5089, DEBIAN-CVE-2026-5089, GHSA-jcwf-qrr5-xwq3, MGASA-2026-0148 and 3 more.