Path Traversal in tar (CVE-2026-45390)
Summary
Path traversal in tar (CVE-2026-45390). Confidential information can be exposed externally. Mitigation: upgrade to 3.5.0, 51ceb0a15982993503c169b9d84456fd50eabe99 or later.
Original description
The description as published by the source.
In OCaml-tar before 3.4.0, a crafted archive with ../ path segments in its name allows escaping the current working directory. This is not desired behavior, and tar(1) rejects such extractions, but ocaml-tar decompresses it anyway. The impact is that it allows arbitrary file writes outside of the desired extraction directory (to an attacker that can reach a tar decompression endpoint).
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory 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 CVE-2026-45390 has been found in tar.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: upgrade tar to 3.5.0, 51ceb0a15982993503c169b9d84456fd50eabe99 or later.
If unsure, ask your IT team or search "tar CVE-2026-45390" on the vendor's site.
CVE-2026-45390 (tar) — CWE-22 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 3.5.0, 51ceb0a15982993503c169b9d84456fd50eabe99 — 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.
Path traversal (CWE-22) exists in tar.
Check the vendor advisory for the affected versions of tar.
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.
Update to 3.5.0, 51ceb0a15982993503c169b9d84456fd50eabe99.
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 'tar' . 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
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1Identify exposure identify
grep -r 'tar' . | 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
tarを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade tar to 3.5.0, 51ceb0a15982993503c169b9d84456fd50eabe99ステージング環境で 3.5.0, 51ceb0a15982993503c169b9d84456fd50eabe99 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。
-
3Post-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
References
- web osv.dev
- web nvd.nist.gov
- web github.com