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Fencer Vulns
high 7.7

CVE-2026-57077 json

YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len

published 2026-07-16 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-45056

cvss
7.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len.

In the bundled libsyck newline_len and is_newline dereference the scan pointer, and the following byte for a "\r\n" pair, with no NUL-terminator or bounds check. During block-scalar lexing at a document boundary the scan runs one byte past the heap lexer buffer. This is an incomplete fix of CVE-2025-11683, on a lexer path the earlier fix did not cover.

Any caller that runs Load or LoadFile on an untrusted document with a block scalar at a document boundary reaches the over-read.

Patch / fix

  • TODDR YAML::Syck 1.47
  • libyaml-syck-perl Debian 12 1.34-2+deb12u3
  • libyaml-syck-perl Debian 13 1.34-2+deb13u3
  • libyaml-syck-perl Debian 14 1.47-1

debian advisories DEBIAN-CVE-2026-57077

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

opensuse advisories openSUSE-SU-2026:21497-1openSUSE-SU-2026:11299-1

  • perl-yaml-syck Alpine 3.24 1.47-r0

alpine advisories ALPINE-CVE-2026-57077

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2026-57077 updated cvss 4.3

YAML::Syck: YAML::Syck: Information disclosure via out-of-bounds read

  • 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
total
Assessed
3 mo ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.7 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CNA 3.1 7.7 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

  • TODDR YAML::Syck

Classification

Weakness

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.