Vulnerability · Published Oct 16, 2025 · Assigned by CPANSec
CVE-2025-11683YAML::Syck versions before 1.36 for Perl has missing Null-Terminators which causes Out-of-Bounds Read and potential Information Disclosure
Medium 6.5
In plain English
A medium-severity memory corruption 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 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libyaml-syck-perl | 1.34-2+deb12u1 | DEBIAN-CVE-2025-11683 |
| Debian:13 | libyaml-syck-perl | 1.34-2+deb13u1 | DEBIAN-CVE-2025-11683 |
| Debian:14 | libyaml-syck-perl | 1.34-4 | DEBIAN-CVE-2025-11683 |
| Ubuntu:25.10 | libyaml-syck-perl | 1.34-3ubuntu0.1 | USN-7844-1 |
| Ubuntu:25.10 | libyaml-syck-perl | 1.34-3ubuntu0.1 | UBUNTU-CVE-2025-11683 |
| Ubuntu:26.04:LTS | libyaml-syck-perl | no fix listed | UBUNTU-CVE-2025-11683 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| TODDR | YAML::Syck | 0 – before 1.36 |
Weakness: CWE-119 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N