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Not in CISA KEV
HIGH severity

CVE-2021-44138 — resin

HIGH

CVE-2021-44138 is a high-severity (CVSS 7.5) Path Traversal vulnerability in com.caucho:resin. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

Path Traversal in Caucho Resin

Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
1 known
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
12.3%probability of exploitation in next 30 days
Moderate Risk0.00%
Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk
0.00%33.3%66.7%100.0%81.6%12.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕com.caucho:resin

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

There is a Directory traversal vulnerability in Caucho Resin, as distributed in Resin 4.0.52 - 4.0.56, which allows remote attackers to read files in arbitrary directories via a ; in a pathname within an HTTP request.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
☕Mavencom.caucho:resin≥ 4.0.52No fix

Affected Products

1 product · 1 configurations
Application
resincaucho
≥ 4.0.52 && ≤ 4.0.56
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

There is a Directory traversal vulnerability in Caucho Resin, as distrib…

github.comNVDApr 2022

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.caucho:resin, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of com.caucho:resin for CVE-2021-44138. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

How to detect CVE-2021-44138

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2021-44138 -u https://target
Template
Caucho Resin >=4.0.52 <=4.0.56 - Directory traversal
Severity
high
Impact
An attacker can exploit this vulnerability to read arbitrary files on the server, potentially leading to unauthorized access or sensitive data exposure.
Remediation
Upgrade Caucho Resin to a version higher than 4.0.56 to mitigate the vulnerability.

Template by ProjectDiscovery nuclei-templates (carrot2), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

There is a Directory traversal vulnerability in Caucho Resin, as distributed in Resin 4.0.52 - 4.0.56, which allows remote attackers to read files in arbitrary directories via a ; in a pathname within an HTTP request.
O3 Security · Impact-Aware SCA

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CVE-2021-44138: resin: Path Traversal in Caucho Resin