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CVE-2026-50631

HIGH 7.4

Published 2026-06-12 · Last modified 2026-06-12

A race condition in AbstractOAuthDataProvider allows concurrent requests using the same Refresh Token to bypass single-use semantics and generate multiple valid Access Tokens, when 'recycleRefreshTokens' is set to false. A leaked refresh token can be replayed concurrently by multiple attackers or threads. Users are recommended to upgrade to versions 4.2.2 or 4.1.7, which fixes this issue.

ELEVATED IMPACT

Severe if exploited (CVSS 7.4), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 21st percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

7.4CVSS 3.1 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-50631/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-50631/poc.json

Affected

Vendors Apache Software Foundation Apache

Products Apache Cxf Cxf

Weakness (CWE)

  • CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Known Affected Software Configurations

VendorProductVersion range
ApacheCxf< 4.1.7
ApacheCxf≥ 4.2.0 and < 4.2.2

All CVSS metrics

  • HIGH 7.4 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
  • HIGH 7.4 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Advisories

Sources: NVD · CVE.org · EPSS