Vulnerability in squid
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 DEBIAN-CVE-2019-12521 has been found in squid.
Risk of unauthorized operations or information disclosure.
What to do: upgrade squid to 4.11-1 or later.
If unsure, ask your IT team or search "squid DEBIAN-CVE-2019-12521" on the vendor's site.
DEBIAN-CVE-2019-12521 (squid)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.11-1 — 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.
A vulnerability (unclassified) exists in squid.
Check the vendor advisory for the affected versions of squid.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 4.11-1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'squid' . 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 exposureidentify
grep -r 'squid' . | 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
squid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 patchpatch
Upgrade squid to 4.11-1ステージング環境で 4.11-1 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 verificationverify
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
| Ecosystem | Package | Affected | Fixed |
|---|---|---|---|
| Debian:12 | squid |
< 4.11-1 |
4.11-1 |
| Debian:13 | squid |
< 4.11-1 |
4.11-1 |
| Debian:14 | squid |
< 4.11-1 |
4.11-1 |
Original description The description as published by the source.
An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
Source: OSV.dev (Open Source Vulnerabilities) OSV
References
- advisory security-tracker.debian.org