🛡️ CVE-2026-57076 on Debian — libyaml-syck-perl

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

Distribution advisory

This page covers CVE-2026-57076 as tracked by Debian, for the package libyaml-syck-perl. The fix is available in version 1.47-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

DEBIAN-CVE-2026-57076 is classified as CWE-416: Use After Free. Memory is used after being released, so its contents may already belong to something else.

Affected software

DEBIAN-CVE-2026-57076 is recorded against 1 package.

libyaml-syck-perl (fixed in 1.47-1)

Timeline and source

Published on 16 July 2026 and last revised on 10 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

Details

Severity Unknown

CVSS Score N/A

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

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2026-07-16

Updated 2026-08-12

Modified 2026-08-10

Fix URL N/A

Affected Packages

Software	From version	Fixed in
libyaml-syck-perl	—	1.47-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2026-57076

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