---
title: "CVE-2026-5089\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-5089?format=md
keywords: index, follow
---

# CVE-2026-5089

Publication date 12 May 2026

Last updated 22 May 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.3 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2026-5089?format=md#impact-score)

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| libyaml-syck-perl | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.3 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | Low |
  | Integrity impact | Low |
  | Availability impact | Low |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.3 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-5089)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-5089)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-5089)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-5089)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-5089>
* <https://lists.security.metacpan.org/cve-announce/msg/39981051/>
* <https://github.com/cpan-authors/YAML-Syck/issues/132>
* <https://github.com/cpan-authors/YAML-Syck/pull/133>