How severe is CVE-2021-21659?

CVE-2021-21659 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-21659?

CVE-2021-21659 affects the following packages: org.jenkins-ci.plugins:urltrigger (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-21659?

Update org.jenkins-ci.plugins:urltrigger to 0.49 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21659 is resolved across your whole dependency graph.

How do I detect CVE-2021-21659 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:urltrigger. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-21659 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-21659?

O3 pinpoints whether CVE-2021-21659 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-21659 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21659 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2021-21659 published, and has it been updated?

CVE-2021-21659 was published on May 25, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2021-21659

HIGH

CVE-2021-21659 is a high-severity (CVSS 8.1) vulnerability in org.jenkins-ci.plugins:urltrigger. O3 Security confirms whether CVE-2021-21659 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

XXE vulnerability in Jenkins URLTrigger Plugin

Also known asGHSA-34j5-c4cv-mmg5

Published

May 25, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Jul 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

☕org.jenkins-ci.plugins:urltrigger

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Jenkins URLTrigger Plugin 0.48 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.jenkins-ci.plugins:urltrigger`	all versions	0.49

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:urltrigger. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.jenkins-ci.plugins:urltrigger to 0.49 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21659 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-21659 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-21659. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Jenkins URLTrigger Plugin 0.48 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

O3 Security · Impact-Aware SCA

Is CVE-2021-21659 in your dependencies?

O3 detects CVE-2021-21659 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works