Jenkins FilePath.untarFrom() (all versions) validates symlink destinations but not targets,...
Summary
Vulnerability reported (CVE-2026-19429). Successful exploitation can lead to full system takeover. Exploitable via POST /job/{name}/build.
Original description
The description as published by the source.
Jenkins FilePath.untarFrom() does not validate symlink targets in extracted TAR archives, even in versions patched for CVE-2026-33001 and CVE-2026-70427. An authenticated attacker with job configuration privileges can include a malicious archive in a build step that creates workspace symlinks pointing to arbitrary files on the Jenkins controller. By reading the secrets directory, the attacker obtains the cryptographic keys used to sign remember-me cookies, forges a valid administrator session cookie without any admin interaction, and gains access to the Script Console for remote code execution. Jenkins 2.576 is additionally affected by a bypass of the CVE-2026-70427 blank-name check via Unicode zero-width characters (U+200B, U+200C, U+200D, U+2060, U+00AD), which Java's String.isBlank() does not recognize as whitespace.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
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-2026-19429 has been found.
Attackers can target a specific entry point like POST /job/{name}/build over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2026-19429" on the vendor's site.
CVE-2026-19429 — CWE-59 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /job/{name}/build / GET /job/{name}/lastBuild/consoleText
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 (CWE-59) has been reported. Attackers reach the vulnerable code path via POST /job/{name}/build.
Check the vendor advisory for the affected versions. Attack surface: POST /job/{name}/build / GET /job/{name}/lastBuild/consoleText.
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /job/{name}/build requests with malformed payloads or SQL meta-characters. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
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2Hunt for indicators of compromise detect
grep 'POST /job/{name}/build' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /job/{name}/buildへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Post-deployment verification verify
Replay attack against POST /job/{name}/build on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。
References
- advisory nvd.nist.gov
- advisory github.com
- advisory jenkins.io
- advisory jenkins.io
- advisory github.com
- web jenkins.io
- web github.com
- web jenkins.io
- web jenkins.io