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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| TODDR | YAML::Syck | < 1.36 | 1.36 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libyaml-syck-perl | 1.34-4 | — |
| Debian 13 | libyaml-syck-perl | 1.34-2+deb13u1 | — |
| Debian 12 | libyaml-syck-perl | 1.34-2+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | libyaml-syck-perl | No fix yet | — |
| Ubuntu 25.10 | libyaml-syck-perl | 1.34-3ubuntu0.1 | USN-7844-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | libyaml-syck-perl | 1.34-2ubuntu0.24.04.1~esm1 | USN-7844-1 |
| Ubuntu Pro 22.04 LTS | libyaml-syck-perl | 1.34-1ubuntu0.1~esm1 | USN-7844-1 |
| Ubuntu Pro 20.04 LTS | libyaml-syck-perl | 1.31-1ubuntu0.1~esm1 | USN-7844-1 |
| Ubuntu Pro 18.04 LTS | libyaml-syck-perl | 1.29-1ubuntu0.18.04.1~esm1 | USN-7844-1 |
| Ubuntu Pro 16.04 LTS | libyaml-syck-perl | 1.29-1ubuntu0.16.04.1~esm1 | USN-7844-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | perl-YAML-Syck | 1.450.0-1.1 | openSUSE-SU-2026:10746-1 |
| openSUSE Leap 16.0 | perl-YAML-Syck | 1.470.0-bp160.1.1 | openSUSE-SU-2026:21497-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | perl-YAML-Syck | 1.36-1.amzn2023.0.1 | ALAS2023-2025-1248 |
| Amazon Linux 2 | perl-YAML-Syck | 1.27-3.amzn2.0.3 | ALAS2-2025-3049 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | perl-YAML +1 | No fix yet | — |
Advisories 6
- WID-SEC-2025-2329 cPanel/WHM (PostgreSQL, Perl): Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 4, 2026
- openSUSE-SU-2026:21497-1 Security update for perl-YAML-Syck SUSE / openSUSE Security Updates · Jul 31, 2026
- USN-7844-1 libyaml-syck-perl vulnerability Ubuntu Security Notices (USN) · Jun 25, 2026
- openSUSE-SU-2026:10746-1 perl-YAML-Syck-1.450.0-1.1 on GA media SUSE / openSUSE Security Updates · May 12, 2026
- ALAS2-2025-3049 Important: perl-YAML-Syck security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Oct 27, 2025
- ALAS2023-2025-1248 Important: perl-YAML-Syck security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Oct 27, 2025