Apache Tomcat: Missing Critical Step in Authentication
CVE-2026-55957 is a high-severity missing critical step in authentication vulnerability in Apache Tomcat from Apache, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Tomcat versions: 11.0.0-M1 through 11.0.4; 10.1.0-M1 through 10.1.36; 9.0.0.M1 through 9.0.100, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.85% chance of exploitation within 30 days, higher than 87% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Tomcat to 9.0.101 or 10.1.37 or 11.0.5, whichever matches your release line, or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Tomcat | 11.0.0-M1 through 11.0.4; 10.1.0-M1 through 10.1.36; 9.0.0.M1 through 9.0.100; 8.5.0 through 8.5.100; 7.0.0 through 7.0.109 | Not stated |
| Apache | Tomcat | before 9.0.101; 10.1.0 up to, but not including, 10.1.37; 11.0.0 up to, but not including, 11.0.5 | 9.0.101, 10.1.37, 11.0.5 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by CISA (ADP).
Official description
Missing Critical Step in Authentication vulnerability in Apache Tomcat when the JNDIRealm was configured to authenticate binds using GSSAPI allowed attackers to authenticate without provided the correct password. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.4, from 10.1.0-M1 through 10.1.36, from 9.0.0.M1 through 9.0.100, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Users are recommended to upgrade to version 11.0.5, 10.1.37 or 9.0.101, which fixes the issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Critical Step in Authentication
The product implements an authentication technique, but it skips a step that weakens the technique.
More Missing Critical Step in Authentication vulnerabilities (CWE-304)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- openwall.com/lists/oss-security/2026/06/29/26Third Party Advisory
Other vulnerabilities in Apache Tomcat
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 8.1 High severity
Recent Missing Critical Step in Authentication vulnerabilities
- 7.3 High severity
- 8.1 High severity
- 7.3 High severity
- 9.8 Critical severity
- 7.2 High severity
- 8.1 High severity
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