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CVE-2026-63687

Apache Cxf vulnerability

9.1 CRITICALEPSS 0.28%
  1. Published6 Aug 2026

Description

Apache CXF's JwtRequestCodeFilter copies all claims from a signed request JWT into the authorization parameter map without excluding security-sensitive parameters. A client that can produce a validly-signed request JWT (e.g., one whose client_secret is known or compromised) can thereby substitute the code_challenge, code_challenge_method, nonce, and state values that were set in the outer HTTP request, undermining PKCE integrity and OpenID Connect replay protection. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Apache Cxf≥ 4.0.0 < 4.1.8 · ≥ 4.2.0 < 4.2.3 · < 3.6.12

Remediation

Fixed in
Apache Cxf≥ 4.1.8

References

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Frequently asked

Is CVE-2026-63687 being actively exploited?

CVE-2026-63687 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.28%.

How severe is CVE-2026-63687?

CVE-2026-63687 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.28% probability of exploitation.

Which products are affected by CVE-2026-63687?

Affected products include Apache Cxf.

How do I fix CVE-2026-63687?

Upgrade affected software to a fixed version, for example Apache Cxf 4.1.8 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-63687 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.