# 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

> An out-of-bounds read in YAML::Syck allows attackers to cause denial of service or disclose memory contents by parsing malicious YAML documents.

- **Severity:** High 7.7 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Jul 2026
- **Updated:** 17 Jul 2026
- **Also known as:** ALPINE-CVE-2026-57077, AZL-109505, AZL-92907, BELL-CVE-2026-57077, DEBIAN-CVE-2026-57077, GHSA-5wqv-8x52-77q2, UBUNTU-CVE-2026-57077

## What is CVE-2026-57077?

CVE-2026-57077 is a high-severity memory corruption vulnerability in TODDR YAML::Syck, published on 16 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### 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.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-57077?


## How do I fix CVE-2026-57077?

Upgrade to a fixed version.

## Is CVE-2026-57077 being exploited?

There is no known exploitation of CVE-2026-57077 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57077 and fix it if it is affected.

What it is: CVE-2026-57077 is a high-severity memory corruption vulnerability in TODDR YAML::Syck, published on 16 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-57077 in the wild and no public exploit code.

Affected product: TODDR YAML::Syck. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-57077/ (Markdown: https://insights.sbomify.com/CVE-2026-57077/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57077
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57077
- OSV: https://osv.dev/vulnerability/CVE-2026-57077

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57077/
Summaries are generated and may contain mistakes; the official description above is the record.