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Fencer Vulns
medium 6.5

CVE-2025-11683 json

YAML::Syck versions before 1.36 for Perl has missing Null-Terminators which causes Out-of-Bounds Read and potential Information Disclosure

published 2025-10-16 12 mo ago modified 2026-10-08 32 d ago also EUVD-2025-34701

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

YAML::Syck versions before 1.36 for Perl has missing null-terminators which causes out-of-bounds read and potential information disclosure

Missing null terminators in token.c leads to but-of-bounds read which allows adjacent variable to be read

The issue is seen with complex YAML files with a hash of all keys and empty values.  There is no indication that the issue leads to accessing memory outside that allocated to the module.

Patch / fix

  • TODDR YAML::Syck 1.36
  • libyaml-syck-perl Debian 12 1.34-2+deb12u1
  • libyaml-syck-perl Debian 13 1.34-2+deb13u1
  • libyaml-syck-perl Debian 14 1.34-4

debian advisories DEBIAN-CVE-2025-11683

  • libyaml-syck-perl Ubuntu 25.10 1.34-3ubuntu0.1
  • libyaml-syck-perl Ubuntu Pro 16.04 LTS 1.29-1ubuntu0.16.04.1~esm1
  • libyaml-syck-perl Ubuntu Pro 18.04 LTS 1.29-1ubuntu0.18.04.1~esm1
  • libyaml-syck-perl Ubuntu Pro 20.04 LTS 1.31-1ubuntu0.1~esm1
  • libyaml-syck-perl Ubuntu Pro 22.04 LTS 1.34-1ubuntu0.1~esm1
  • libyaml-syck-perl Ubuntu Pro 24.04 LTS 1.34-2ubuntu0.24.04.1~esm1

ubuntu advisories UBUNTU-CVE-2025-11683

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • perl-YAML-Syck openSUSE Leap 16.0 1.470.0-bp160.1.1
  • perl-YAML-Syck openSUSE Tumbleweed 1.450.0-1.1

opensuse advisories openSUSE-SU-2026:21497-1openSUSE-SU-2026:10746-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-11683 updated cvss 6.5

yaml-syck: YAML::Syck potential Information Disclosure

  • Red Hat Enterprise Linux 6 perl-YAML-Syck Red Hat Enterprise Linux 7 perl-YAML-Syck
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perl-YAML-Syck
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
12 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

  • TODDR YAML::Syck

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.