Description
The payload length in a WebSocket frame was not correctly validated in Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M1 to 9.0.36, 8.5.0 to 8.5.56 and 7.0.27 to 7.0.104. Invalid payload lengths could trigger an infinite loop. Multiple requests with invalid payload lengths could lead to a denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Apache Tomcat | Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M1 to 9.0.36, 8.5.0 to 8.5.56, 7.0.27 to 7.0.104 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | tomcat9 | 9.0.37-1 | — |
| Debian 13 | tomcat9 | 9.0.37-1 | — |
| Debian 12 | tomcat9 | 9.0.37-1 | — |
| Debian 10 | tomcat9 | 9.0.31-1~deb10u2 | DSA-4727-1 |
| Debian 9 | tomcat8 | 8.5.54-0+deb9u3 | DLA-2286-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | tomcat9 | 9.0.31-1ubuntu0.1 | USN-4596-1 |
| Ubuntu 16.04 LTS | tomcat8 | 8.0.32-1ubuntu1.13 | USN-4448-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | tomcat8 +1 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | tomcat7 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | tomcat7 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | tomcat +9 | 7.0.76-15.el7 | RHSA-2020:4004 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Web Server 5 | jws5-tomcat +9 | 9.0.30-5.redhat_6.1.el6jws | RHSA-2020:3306 |
| Red Hat JBoss Web Server 3 | tomcat7 +11 | 7.0.70-41.ep7.el6 | RHSA-2020:3303 |
| Red Hat JBoss Web Server 3 | tomcat8 +11 | 8.0.36-45.ep7.el6 | RHSA-2020:3303 |
| Red Hat JBoss EAP 6 | jboss-as-ee +61 | 7.5.24-2.Final_redhat_00001.1.ep6.el6 | RHSA-2022:5460, RHSA-2022:5459 |
| Red Hat JBoss EAP 6 | jbossas-javadocs | 7.5.24-1.Final_redhat_00001.1.ep6.el6 | RHSA-2022:5460, RHSA-2022:5459 |
| Red Hat JBoss EAP 6 | jbossts | 1:4.17.45-2.Final_redhat_2.1.ep6.el6 | RHSA-2022:5460, RHSA-2022:5459 |
| Red Hat JBoss EAP 6 | jbossweb | 7.5.31-2.Final_redhat_2.1.ep6.el5 | RHSA-2022:5460, RHSA-2022:5459, RHSA-2020:3383 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | tomcat | 9.0.36-3.6.1 | SUSE-SU-2020:2047-1 |
| SLES 15 SP1 | tomcat | 9.0.36-4.41.2 | SUSE-SU-2020:2046-1 |
| SLES 15 | tomcat | 9.0.36-3.65.2 | SUSE-SU-2020:2045-1 |
| SLES 12 SP5 | tomcat | 9.0.36-3.45.1 | SUSE-SU-2026:1058-1, SUSE-SU-2020:2037-1 |
| SLES 12 SP4 | tomcat | 9.0.36-3.45.1 | SUSE-SU-2020:2037-1 |
Show 15 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SLES 12 SP2 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SLES for SAP 15 | tomcat | 9.0.36-3.65.2 | SUSE-SU-2020:2045-1 |
| SLES for SAP 12 SP5 | tomcat | 9.0.36-3.45.1 | SUSE-SU-2020:2037-1 |
| SLES for SAP 12 SP4 | tomcat | 9.0.36-3.45.1 | SUSE-SU-2020:2037-1 |
| SLES for SAP 12 SP3 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SLES for SAP 12 SP2 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SLE HPC 15 | tomcat | 9.0.36-3.65.2 | SUSE-SU-2020:2045-1 |
| SUSE OpenStack Cloud Crowbar 9 | tomcat | 9.0.36-3.45.1 | SUSE-SU-2020:2037-1 |
| SUSE OpenStack Cloud Crowbar 8 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SUSE OpenStack Cloud 9 | tomcat | 9.0.36-3.45.1 | SUSE-SU-2020:2037-1 |
| SUSE OpenStack Cloud 8 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SUSE OpenStack Cloud 7 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SUSE HPE Helion OpenStack 8 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
| SUSE Enterprise Storage 5 | tomcat | 8.0.53-29.37.1 | SUSE-SU-2020:2611-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | tomcat | 9.0.43-8.1 | openSUSE-SU-2024:12103-1 |
| openSUSE Tumbleweed | tomcat10 | 10.1.14-1.1 | openSUSE-SU-2024:13441-1 |
| openSUSE Leap 15.2 | tomcat | 9.0.36-lp152.2.4.1 | openSUSE-SU-2020:1111-1 |
| openSUSE Leap 15.1 | tomcat | 9.0.36-lp151.3.27.1 | openSUSE-SU-2020:1102-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | tomcat +9 | 7.0.76-10.amzn2.0.4 | ALAS2-2023-2047 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | tomcat +9 | 7.0.76-15.el7 | ELSA-2020-4004 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 2 repositories
-
RedTeamPentesting/CVE-2020-13935 ★ 167 · Nov 2, 2020
Exploit for WebSocket Vulnerability in Apache Tomcat
-
aabbcc19191/CVE-2020-13935 ★ 0 · Jun 2, 2022
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Affected packages
Advisories 28
- RHSA-2022:5460 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 6.4.24 security update Red Hat Security Advisories (RHSA) · Oct 13, 2026
- RHSA-2022:5459 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 6.4.24 security update Red Hat Security Advisories (RHSA) · Oct 13, 2026
- RHSA-2020:4004 Red Hat Security Advisory: tomcat security and bug fix update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2020:3383 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 6.4 security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2020:3303 Red Hat Security Advisory: Red Hat JBoss Web Server 3.1 Service Pack 10 security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2020:3306 Red Hat Security Advisory: Red Hat JBoss Web Server 5.3.2 security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- USN-4596-1 tomcat9 vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4448-1 tomcat8 vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- SUSE-SU-2026:1058-1 Security update for tomcat SUSE / openSUSE Security Updates · Mar 27, 2026
- WID-SEC-2022-0519 Apache Tomcat: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Mar 26, 2026
- DSA-4727-1 tomcat9 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2286-1 tomcat8 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2020:2037-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2045-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2611-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1111-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1102-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2046-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2047-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13441-1 tomcat10-10.1.14-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2026-0205 Oracle MySQL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jan 25, 2026
- WID-SEC-2022-1375 JFrog Artifactory: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 12, 2025
- openSUSE-SU-2024:12103-1 tomcat-9.0.43-8.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- NCSC-2025-0123 Kwetsbaarheden verholpen in Oracle Database Producten NCSC-NL (Netherlands) · Apr 16, 2025
- WID-SEC-2024-0528 Dell Data Protection Advisor: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 29, 2024
- WID-SEC-2023-1048 Oracle Construction and Engineering: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 4, 2024
- ALAS2-2023-2047 Important: tomcat security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · May 16, 2023
- ELSA-2020-4004 Important: tomcat security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 6, 2020
References
- https://lists.apache.org/thread.html/rd48c72bd3255bda87564d4da3791517c074d94f8a701f93b85752651%40%3Cannounce.tomcat.apache.org%3E
- DSA-4727 vendor-advisory
- [debian-lts-announce] 20200722 [SECURITY] [DLA 2286-1] tomcat8 security update mailing-list
- openSUSE-SU-2020:1102 vendor-advisory
- openSUSE-SU-2020:1111 vendor-advisory
- USN-4448-1 vendor-advisory
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://security.netapp.com/advisory/ntap-20200724-0003/
- https://kc.mcafee.com/corporate/index?page=content&id=SB10332
- USN-4596-1 vendor-advisory
- [tomcat-users] 20201118 Re: Strange crash-on-takeoff, Tomcat 7.0.104 mailing-list
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html