VulnerabilityPublished 27 Aug 2026Updated 17 Oct 2026

CVE-2026-63676: Libyaml perl · backtracking leading to exponential load time

Affects libyaml-perlSource GCVE Database

Not known to be exploited · fixed in 1.30-1ubuntu0.22.04.1 : update libyaml-perl when convenient.

Data as of 18 Oct 2026, 04:22 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in 1.30-1ubuntu0.22.04.1, 1.31-1ubuntu0.24.04.1, 1.15-1ubuntu0.1~esm1 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Ubuntu 26.10libyaml-perl`pkg:deb/ubuntu/libyaml-perl?arch=source&distro=stonking`Other threats	Affected =1.31-1	Fixed in–
Ubuntu 26.04 LTSlibyaml-perl`pkg:deb/ubuntu/libyaml-perl?arch=source&distro=resolute`Other threats	Affected =1.31-1	Fixed in–
Ubuntu Pro 26.04 LTSlibyaml-perl`pkg:deb/ubuntu/libyaml-perl?arch=source&distro=esm-apps/resolute`Other threats	Affected <1.31-1ubuntu0.26.04.1~esm1	Fixed in 1.31-1ubuntu0.26.04.1~esm1
Ubuntu 24.04 LTSlibyaml-perl`pkg:deb/ubuntu/libyaml-perl?arch=source&distro=noble`Other threats	Affected <1.31-1ubuntu0.24.04.1	Fixed in 1.31-1ubuntu0.24.04.1
Ubuntu 22.04 LTSlibyaml-perl`pkg:deb/ubuntu/libyaml-perl?arch=source&distro=jammy`Other threats	Affected <1.30-1ubuntu0.22.04.1	Fixed in 1.30-1ubuntu0.22.04.1
Ubuntu 20.04 LTSlibyaml-perl`pkg:deb/ubuntu/libyaml-perl?arch=source&distro=focal`Other threats	Affected =1.29-1 =1.30-1	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and should be applied by upgrading to perl-YAML-1.320.0-1.1 or later. Users should update affected libyaml-perl packages to the fixed version provided by their distribution. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-63676 is a security vulnerability in the libyaml-perl package causing backtracking that leads to exponential load time. This issue affects multiple specific versions of libyaml-perl and has been fixed in perl-YAML-1.320.0-1.1 on openSUSE Tumbleweed. The vulnerability is rated medium severity and no known exploits are reported in the wild. A patch is available to address this issue.

Impact

The vulnerability can cause excessive processing time due to backtracking, which may lead to denial of service or degraded performance when processing YAML data with affected libyaml-perl versions. There are no reports of active exploitation in the wild.

Summary

The vulnerability identified as CVE-2026-63676 involves backtracking in libyaml-perl that results in exponential load time, potentially causing performance degradation or denial of service conditions. This issue affects several specific versions of libyaml-perl prior to the fixed release perl-YAML-1.320.0-1.1. The problem has been resolved in the updated package distributed on openSUSE Tumbleweed. No CVSS score is provided, and no active exploitation has been reported.

References

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