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CVE-2026-65905

CRITICAL 9.8

Published 2026-08-25 · Last modified 2026-08-26

Authentication Bypass by Capture-replay vulnerability in Apache Tomcat's DIGEST authenticator. If, before windowSize requests have been made, a client makes a DIGEST authenticated request with a nonceCount on the upper boundary of the replay window then that request is replayable once only while the associated nonceCount remains within the replay window.   This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.24, from 10.1.0-M1 through 10.1.57, from 9.0.0.M1 through 9.0.120. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.30 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fix the issue.

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.8%chance of exploitation in 30 days · 53rd percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

9.8CVSS 3.1 · CRITICAL

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

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: No special conditions — reliably repeatable

✓ 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-2026-65905/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-2026-65905/poc.json

Affected

Vendors Apache Software Foundation Apache

Products Apache Tomcat Tomcat

Weakness (CWE)

  • CWE-294: Authentication Bypass by Capture-replay

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
ApacheTomcat≥ 7.0.30 and ≤ 7.0.109
ApacheTomcat≥ 8.5.0 and < 9.0.121
ApacheTomcat≥ 10.1.0 and < 10.1.58
ApacheTomcat≥ 11.0.0 and < 11.0.25

All CVSS metrics

  • CRITICAL 9.8 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Advisories

Sources: NVD · CVE.org · EPSS