How severe is CVE-2026-57294?

CVE-2026-57294 has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-57294?

CVE-2026-57294 affects the following packages: com.amazon.jenkins.fleet:ec2-fleet (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-57294?

Update com.amazon.jenkins.fleet:ec2-fleet to 4.2.3.540.va or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57294 is resolved across your whole dependency graph.

How do I detect CVE-2026-57294 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.amazon.jenkins.fleet:ec2-fleet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-57294 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.

Is CVE-2026-57294 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-57294 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.

What is the EPSS score for CVE-2026-57294?

CVE-2026-57294 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 16th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2026-57294 published, and has it been updated?

CVE-2026-57294 was published on June 24, 2026 and was last updated on September 25, 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

MEDIUM severity

CVE-2026-57294 — ec2-fleet

MEDIUMFix: jenkinsci/ec2-fleet-plugin#531

CVE-2026-57294 is a medium-severity (CVSS 5.4) vulnerability in com.amazon.jenkins.fleet:ec2-fleet. A fix is available for com.amazon.jenkins.fleet:ec2-fleet — see the affected versions and patch details below.

Jenkins EC2 Fleet Plugin has a missing permission check

Published

Jun 24, 2026

Updated

Sep 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-57294.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs16th percentile — riskier than 16% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2026-57294 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

☕com.amazon.jenkins.fleet:ec2-fleet

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 EC2 Fleet Plugin 4.2.3.539.v8fedff2a_81c3 and earlier does not perform permission checks in several HTTP endpoints used to validate cloud configurations.

This allows attackers with Overall/Read permission to connect to an attacker-specified URL using attacker-specified credentials IDs obtained through another method, capturing AWS credentials stored in Jenkins.

Additionally, these HTTP endpoints do not require POST requests, resulting in a cross-site request forgery (CSRF) vulnerability.

EC2 Fleet Plugin 4.2.3.540.va_6eedb_7b_c112 requires Overall/Administer permission and POST requests to perform these form validation actions.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.amazon.jenkins.fleet:ec2-fleet`	all versions	4.2.3.540.va`com.amazon.jenkins.fleet:ec2-fleet:4.2.3.540.va`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.amazon.jenkins.fleet:ec2-fleet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update com.amazon.jenkins.fleet:ec2-fleet to 4.2.3.540.va or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57294 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.

Frequently Asked Questions

Jenkins EC2 Fleet Plugin 4.2.3.539.v8fedff2a_81c3 and earlier does not perform permission checks in several HTTP endpoints used to validate cloud configurations. This allows attackers with Overall/Read permission to connect to an attacker-specified URL using attacker-specified credentials IDs obtained through another method, capturing AWS credentials stored in Jenkins. Additionally, these HTTP endpoints do not require POST requests, resulting in a cross-site request forgery (CSRF) vulnerability. EC2 Fleet Plugin 4.2.3.540.va_6eedb_7b_c112 requires Overall/Administer permission and POST requ

O3 Security · Impact-Aware SCA

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