Description
While investigating bug 64830 it was discovered that Apache Tomcat 10.0.0-M1 to 10.0.0-M9, 9.0.0-M1 to 9.0.39 and 8.5.0 to 8.5.59 could re-use an HTTP request header value from the previous stream received on an HTTP/2 connection for the request associated with the subsequent stream. While this would most likely lead to an error and the closure of the HTTP/2 connection, it is possible that information could leak between requests.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache Tomcat | Apache Tomcat 10 10.0.0-M1 to 10.0.0-M9, Apache Tomcat 9 9.0.0-M1 to 9.0.39, Apache Tomcat 8.5 8.5.0 to 8.5.59 | — |
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 | 9.0.40-1 | — |
| Debian 13 | tomcat9 | 9.0.40-1 | — |
| Debian 12 | tomcat9 | 9.0.40-1 | — |
| Debian 10 | tomcat9 | 9.0.31-1~deb10u3 | DSA-4835-1 |
| Debian 9 | tomcat8 | 8.5.54-0+deb9u5 | DLA-2495-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | tomcat9 | 9.0.31-1ubuntu0.2 | USN-5360-1 |
| Ubuntu 18.04 LTS | tomcat9 | 9.0.16-3ubuntu0.18.04.2 | USN-5360-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | tomcat8 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Web Server 5 | jws5-tomcat +9 | 9.0.36-9.redhat_8.1.el7jws | RHSA-2021:0494 |
| Red Hat JBoss Web Server 5 | jws5-tomcat-native | 1.2.25-3.redhat_3.el7jws | RHSA-2021:0494 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | tomcat | 9.0.36-3.18.1 | SUSE-SU-2021:0041-1 |
| SLES 15 SP1 | tomcat | 9.0.36-4.53.1 | SUSE-SU-2021:0042-1 |
| SLES 15 | tomcat | 9.0.36-3.74.1 | SUSE-SU-2021:0040-1 |
| SLES 12 SP5 | tomcat | 9.0.36-3.58.1 | SUSE-SU-2026:1058-1, SUSE-SU-2021:0031-1 |
| SLES 12 SP4 | tomcat | 9.0.36-3.58.1 | SUSE-SU-2021:0031-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 | tomcat | 9.0.36-3.74.1 | SUSE-SU-2021:0040-1 |
| SLES for SAP 12 SP5 | tomcat | 9.0.36-3.58.1 | SUSE-SU-2021:0031-1 |
| SLES for SAP 12 SP4 | tomcat | 9.0.36-3.58.1 | SUSE-SU-2021:0031-1 |
| SLE HPC 15 | tomcat | 9.0.36-3.74.1 | SUSE-SU-2021:0040-1 |
| SUSE OpenStack Cloud Crowbar 9 | tomcat | 9.0.36-3.58.1 | SUSE-SU-2021:0031-1 |
| SUSE OpenStack Cloud 9 | tomcat | 9.0.36-3.58.1 | SUSE-SU-2021:0031-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | tomcat | 9.0.36-8.4 | openSUSE-SU-2024:11468-1 |
| openSUSE Tumbleweed | tomcat10 | 10.1.14-1.1 | openSUSE-SU-2024:13441-1 |
| openSUSE Leap 15.2 | tomcat | 9.0.36-lp152.2.16.1 | openSUSE-SU-2021:0043-1 |
| openSUSE Leap 15.1 | tomcat | 9.0.36-lp151.3.39.1 | openSUSE-SU-2021:0081-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | tomcat | No fix yet | — |
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 1 repository
-
forse01/CVE-2020-17527-Tomcat ★ 2 · Feb 5, 2021
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.apache.tomcat:tomcat-coyote | >= 10.0.0-M1, < 10.0.0-M10 | 10.0.0-M10 | GHSA-vvw4-rfwf-p6hx |
| Maven | org.apache.tomcat:tomcat-coyote | >= 9.0.0-M1, < 9.0.40 | 9.0.40 | GHSA-vvw4-rfwf-p6hx |
| Maven | org.apache.tomcat:tomcat-coyote | >= 8.5.0, < 8.5.60 | 8.5.60 | GHSA-vvw4-rfwf-p6hx |
Advisories 15
- RHSA-2021:0494 Red Hat Security Advisory: Red Hat JBoss Web Server 5.4.1 Security Update Red Hat Security Advisories (RHSA) · Oct 2, 2026
- USN-5360-1 tomcat9 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-2023-2466 Apache Tomcat: Schwachstelle ermöglicht Offenlegung von Informationen BSI CERT-Bund (WID) · Mar 26, 2026
- DSA-4835-1 tomcat9 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2495-1 tomcat8 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2021:0031-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0041-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0042-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11468-1 tomcat-9.0.36-8.4 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0081-1 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
- SUSE-SU-2021:0040-1 Security update for tomcat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0043-1 Security update for tomcat SUSE / openSUSE Security Updates · May 7, 2025
- WID-SEC-2023-0065 Oracle MySQL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 27, 2023
References
- https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E
- [tomcat-dev] 20201203 [SECURITY] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [tomcat-dev] 20201203 svn commit: r1884073 - in /tomcat/site/trunk: docs/security-10.html docs/security-8.html docs/security-9.html xdocs/security-10.xml xdocs/security-8.xml xdocs/security-9.xml mailing-list
- [announce] 20201203 [SECURITY] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [tomcat-users] 20201203 [SECURITY] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [oss-security] 20201203 [SECURITY] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [guacamole-issues] 20201206 [jira] [Created] (GUACAMOLE-1229) Fix in Dockerhub for latest CVE-2020-17527 mailing-list
- [guacamole-issues] 20201206 [jira] [Commented] (GUACAMOLE-1229) Fix in Dockerhub for latest CVE-2020-17527 mailing-list
- [tomee-commits] 20201207 [jira] [Created] (TOMEE-2936) TomEE plus(7.0.9) is affected by CVE-2020-17527(BDSA-2020-3628) vulnerability. mailing-list
- [tomee-commits] 20201207 [jira] [Assigned] (TOMEE-2936) TomEE plus(7.0.9) is affected by CVE-2020-17527(BDSA-2020-3628) vulnerability. mailing-list
- [debian-lts-announce] 20201216 [SECURITY] [DLA 2495-1] tomcat8 security update mailing-list
- GLSA-202012-23 vendor-advisory
- [tomcat-dev] 20210114 svn commit: r1885488 - in /tomcat/site/trunk: docs/security-10.html docs/security-7.html docs/security-8.html docs/security-9.html xdocs/security-10.xml xdocs/security-7.xml xdocs/security-8.xml xdocs/security-9.xml mailing-list
- [announce] 20210119 Re: [SECURITY][CORRECTION] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [tomcat-dev] 20210119 Re: [SECURITY][CORRECTION] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [tomcat-announce] 20210119 Re: [SECURITY][CORRECTION] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- [tomcat-users] 20210119 Re: [SECURITY][CORRECTION] CVE-2020-17527 Apache Tomcat HTTP/2 Request header mix-up mailing-list
- DSA-4835 vendor-advisory
- [tomee-commits] 20210319 [jira] [Updated] (TOMEE-2936) TomEE plus(7.0.9) is affected by CVE-2020-17527(BDSA-2020-3628) vulnerability. mailing-list
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://security.netapp.com/advisory/ntap-20201210-0003/
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html