9.1

CVE-2026-63687: apache software foundation apache cxf

CVSS: 9.1v3.1CriticalModified
Published 06-08-2026Last modified 07-08-2026
Open JSON

Vulnerability summary

CVE-2026-63687 is a critical (CVSS 9.1) vulnerability in apache software foundation apache cxf. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.3% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.28%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 06-08-2026
    PublishedVulnerability first disclosed.
  2. 07-08-2026
    Last modifiedVulnerability information updated.

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

+0.02 pp

From 0.27% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.28%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Apache1 product
  • cxf< 3.6.12 | ≥ 4.0.0, < 4.1.8 | ≥ 4.2.0, < 4.2.3
Apache software foundation1 product
  • apache cxf≥ 4.2.0, < 4.2.3 | ≥ 4.0.0, < 4.1.8 | < 3.6.12

2 vendors · 2 products

References

2 links