CVE-2026-76183
CRITICALDescription
Authentication Bypass by Alternate Name vulnerability in Apache Tomcat allowed the security constraints for any WebSocket endpoint to be bypassed. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121. The following versions were EOS at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.43 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 31% of all known CVEs.
References
Related Vulnerabilities
Other CWE-289 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-56511 | Critical | 9.8 | 44% | - | Fix |
| CVE-2021-34746 | Critical | 9.8 | 18% | - | Fix |
| CVE-2017-16590 | High | 8.8 | 3.3% | - | - |
| CVE-2026-48618 | Medium | 6.5 | 3.2% | - | Fix |
| CVE-2025-55130 | Critical | 9.1 | 1.7% | - | Fix |
| CVE-2023-20046 | High | 8.8 | 0.9% | - | Fix |
Common questions
How do I fix CVE-2026-76183?
Upgrade tomcat10 on debian unstable to 10.1.60-1 or later.
Is CVE-2026-76183 being actively exploited?
Not that we know of. CVE-2026-76183 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.39% is the estimated probability that it will be exploited in the next 30 days. That is higher than 31% of all scored CVEs.
How severe is CVE-2026-76183?
CVE-2026-76183 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-76183 affect?
Published advisories record a fix for tomcat10 (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-30.