Vulnerability · Published Jul 16, 2026 · Assigned by CPANSec
CVE-2026-57077YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len
High 7.7
In plain English
A high-severity out-of-bounds read in YAML::Syck from TODDR. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | perl-yaml-syck | 1.47-r0 | ALPINE-CVE-2026-57077 |
| Debian:12 | libyaml-syck-perl | 1.34-2+deb12u3 | DEBIAN-CVE-2026-57077 |
| Debian:13 | libyaml-syck-perl | 1.34-2+deb13u3 | DEBIAN-CVE-2026-57077 |
| Debian:14 | libyaml-syck-perl | 1.47-1 | DEBIAN-CVE-2026-57077 |
| Ubuntu:26.04:LTS | libyaml-syck-perl | no fix listed | UBUNTU-CVE-2026-57077 |
| Ubuntu:26.10 | libyaml-syck-perl | no fix listed | UBUNTU-CVE-2026-57077 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| TODDR | YAML::Syck | 0 – before 1.47 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H