In Apache Tomcat 9.0.0.M1 to 9.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99 the HTTP header parsing code used an approach to end-of-line…

Description

In Apache Tomcat 9.0.0.M1 to 9.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99 the HTTP header parsing code used an approach to end-of-line parsing that allowed some invalid HTTP headers to be parsed as valid. This led to a possibility of HTTP Request Smuggling if Tomcat was located behind a reverse proxy that incorrectly handled the invalid Transfer-Encoding header in a particular manner. Such a reverse proxy is considered unlikely.

Scores

EPSS (exploitation in 30 days)

9.4% · top 4.6% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.8.

Weakness

• HTTP Request Smuggling
• CWE-444 (opens in a new tab)All about CWE-444 and its CVEs

Affected products

• Apache · Apache Tomcat

  • affected Apache Tomcat 9.0.0.M1 to 9.0.30
  • affected 8.5.0 to 8.5.50
  • affected 7.0.0 to 7.0.99

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Mavenorg.apache.tomcat.embed:tomcat-embed-coreGHSA-qxf4-chvg-4r8r (opens in a new tab)
• Mavenorg.apache.tomcat:tomcatGHSA-qxf4-chvg-4r8r (opens in a new tab)

References (19)

• [tomcat-announce] 20200224 [SECURITY] CVE-2020-1935 HTTP Request Smuggling (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [debian-lts-announce] 20200304 [SECURITY] [DLA 2133-1] tomcat7 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• openSUSE-SU-2020:0345 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• [tomee-commits] 20200320 [jira] [Created] (TOMEE-2790) TomEE plus(7.0.7) is affected by CVE-2020-1935 & CVE-2019-17569 vulnerabilities (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomee-commits] 20200323 [jira] [Commented] (TOMEE-2790) TomEE plus(7.0.7) is affected by CVE-2020-1935 & CVE-2019-17569 vulnerabilities (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• DSA-4673 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
• DSA-4680 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
• [debian-lts-announce] 20200528 [SECURITY] [DLA 2209-1] tomcat8 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• https://www.oracle.com/security-alerts/cpujul2020.html (opens in a new tab)x_refsource_MISCx_transferred
• https://security.netapp.com/advisory/ntap-20200327-0005/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• [tomcat-users] 20200724 CVE-2020-1935 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-users] 20200724 Re: CVE-2020-1935 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-users] 20200724 RE: CVE-2020-1935 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-users] 20200726 Re: CVE-2020-1935 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-users] 20200727 RE: CVE-2020-1935 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• USN-4448-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• https://www.oracle.com/security-alerts/cpuoct2020.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.oracle.com/security-alerts/cpujan2021.html (opens in a new tab)x_refsource_MISCx_transferred
• [tomcat-dev] 20210428 [Bug 65272] Problems proccessing HTTP request without CR in last versions (opens in a new tab)mailing-listx_refsource_MLISTx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-qxf4-chvg-4r8r (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2020-1935](https://trackcve.app/badge/CVE-2020-1935.svg)](https://trackcve.app/cve/CVE-2020-1935)

Record last updated 8 Oct 2026, 21:03 UTC.