Vulnerability in perl-yaml-syck (ALPINE-CVE-2026-57076)

Summary

Vulnerability in perl-yaml-syck (ALPINE-CVE-2026-57076). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 1.47-r0 or later.

Original description

The description as published by the source.

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor.

In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path.

Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as ALPINE-CVE-2026-57076 has been found in perl-yaml-syck.
Successful exploitation can lead to full system takeover.
What to do: upgrade perl-yaml-syck to 1.47-r0 or later.
If unsure, ask your IT team or search "perl-yaml-syck ALPINE-CVE-2026-57076" on the vendor's site.

ALPINE-CVE-2026-57076 (perl-yaml-syck)
Attack vector: local / no user interaction
Patched: 1.47-r0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in perl-yaml-syck.

📍 Affected scope

Check the vendor advisory for the affected versions of perl-yaml-syck.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 1.47-r0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'perl-yaml-syck' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'perl-yaml-syck' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で perl-yaml-syck を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade perl-yaml-syck to 1.47-r0
```
ステージング環境で 1.47-r0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Alpine:v3.24 perl-yaml-syck

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.47-r0"}]}]

References

advisory security.alpinelinux.org