CVE-2026-57077

HIGHCVSS 7.7/10EPSS 0.19%

Last modified

CVE-2026-57077 is a high-severity vulnerability rated 7.7/10 on the CVSS scale. 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. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
7.7/10

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

EPSS Probability
0.19%

8.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
TODDRYAML::Syck< 1.47

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-57077?
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.
How severe is CVE-2026-57077?
CVE-2026-57077 has a CVSS score of 7.7/10 (HIGH severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.
How do I fix CVE-2026-57077?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST