VulnerabilityDeferred

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.

HIGH 7.7EPSS 0.14%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1: 7.7 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS: 0.14% probability · 4th percentile
CISA KEV: Not listed
Weakness: CWE-125
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.