# CVE-2026-57077: libyaml-syck-perl: YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len

CVE-2026-57077 is fixed in 5 products on 1 platform, first by FEDORA-2026-C8484F1AFB, released July 14, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-57077
- Priority: High
- CVSS: 7.7 (high)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 14, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libyaml-syck-perl Debian 12.15 (bookworm) | 1.34-2+deb12u3 | [DEBIAN-CVE-2026-57077](https://patchblox.com/security/data/fix/linux/debian-cve-2026-57077.md) | Jul 19, 2026 |
| Linux | libyaml-syck-perl Debian 13.5 (trixie) | 1.34-2+deb13u3 | [DEBIAN-CVE-2026-57077](https://patchblox.com/security/data/fix/linux/debian-cve-2026-57077.md) | Jul 19, 2026 |
| Linux | libyaml-syck-perl Debian 14 | 1.47-1 | [DEBIAN-CVE-2026-57077](https://patchblox.com/security/data/fix/linux/debian-cve-2026-57077.md) | Jul 19, 2026 |
| Linux | perl-YAML-Syck Fedora 43 | 1.47-1.fc43 | [FEDORA-2026-C8484F1AFB](https://patchblox.com/security/data/fix/linux/fedora-2026-c8484f1afb.md) | Jul 14, 2026 |
| Linux | perl-YAML-Syck amzn 2023 | 1.37-1.amzn2023.0.4 | [ALAS2023-2026-2007](https://patchblox.com/security/data/fix/linux/alas2023-2026-2007.md) | Aug 3, 2026 |
| Linux | perl-YAML-Syck opensuse-leap 16.0 | 1.470.0-bp160.1.1 | [OPENSUSE-SU-2026:21497-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21497-1.md) | Jul 29, 2026 |
| Linux | perl-YAML-Syck-debuginfo Fedora 43 | 1.47-1.fc43 | [FEDORA-2026-C8484F1AFB](https://patchblox.com/security/data/fix/linux/fedora-2026-c8484f1afb.md) | Jul 14, 2026 |
| Linux | perl-YAML-Syck-debuginfo amzn 2023 | 1.37-1.amzn2023.0.4 | [ALAS2023-2026-2007](https://patchblox.com/security/data/fix/linux/alas2023-2026-2007.md) | Aug 3, 2026 |
| Linux | perl-YAML-Syck-debugsource Fedora 43 | 1.47-1.fc43 | [FEDORA-2026-C8484F1AFB](https://patchblox.com/security/data/fix/linux/fedora-2026-c8484f1afb.md) | Jul 14, 2026 |
| Linux | perl-YAML-Syck-debugsource amzn 2023 | 1.37-1.amzn2023.0.4 | [ALAS2023-2026-2007](https://patchblox.com/security/data/fix/linux/alas2023-2026-2007.md) | Aug 3, 2026 |
| Linux | perl-YAML-Syck-tests amzn 2023 | 1.37-1.amzn2023.0.4 | [ALAS2023-2026-2007](https://patchblox.com/security/data/fix/linux/alas2023-2026-2007.md) | Aug 3, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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