--- title: "CVE-2026-55955\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2026-55955?format=md keywords: index, follow --- # CVE-2026-55955 Publication date 29 June 2026 Last updated 1 July 2026 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **6.5 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2026-55955?format=md#impact-score) Toggle side navigation ## Description Improper Authentication vulnerability in Apache Tomcat allowed a replay attack against the EncryptionInterceptor in the cluster component. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.13 through 9.0.18, from 8.5.38 through 8.5.100, from 7.0.100 through 7.0.109. Users are recommended to upgrade to version 11.0.23, 10.1.56, 9.0.119, which fixes the issue. [Read the notes from the security team](https://ubuntu.com/security/CVE-2026-55955?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | tomcat6 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Needs evaluation | | tomcat7 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 18.04 LTS bionic | Not affected | | 16.04 LTS xenial | Needs evaluation | | 14.04 LTS trusty | Needs evaluation | | tomcat8 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 18.04 LTS bionic | Needs evaluation | | 16.04 LTS xenial | Needs evaluation | | tomcat9 | 26.04 LTS resolute | Needs evaluation | | 25.10 questing | Ignored end of life, was needs-triage | | 24.04 LTS noble | Needs evaluation | | 22.04 LTS jammy | Needs evaluation | | 20.04 LTS focal | Needs evaluation | | 18.04 LTS bionic | Needs evaluation | | tomcat10 | 26.04 LTS resolute | Needs evaluation | | 25.10 questing | Ignored end of life, was needs-triage | | 24.04 LTS noble | Needs evaluation | | 22.04 LTS jammy | Not in release | | tomcat11 | 26.04 LTS resolute | Needs evaluation | | 25.10 questing | Ignored end of life, was needs-triage | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ## Notes --- ### [ebarretto](https://launchpad.net/~ebarretto) xenial tomcat6 only builds libservlet2.5-java, not the Tomcat server binaries bionic tomcat7 only builds libservlet3.0-java, not the Tomcat server binaries ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 6.5 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Network | | Attack complexity | Low | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | Low | | Integrity impact | Low | | Availability impact | None | * Scores | Parameter | Value | | --- | --- | | Base score | 6.5 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-55955) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-55955) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-55955) * [Debian](https://security-tracker.debian.org/tracker/CVE-2026-55955) ### Other references * * * * * *