Potential HTTP request smuggling in Apache Tomcat
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.apache.tomcat.embed:tomcat-embed-core | < 7.0.100, >= 8.0.0, < 8.5.51, >= 9.0.0, < 9.0.31 | 7.0.100, 8.5.51, 9.0.31 |
| Java / Kotlin (Maven) | org.apache.tomcat:tomcat | < 7.0.100, >= 8.0.0, < 8.5.51, >= 9.0.0, < 9.0.31 | 7.0.100, 8.5.51, 9.0.31 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2020-1935
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.debian.org/security/2020/dsa-4680
- https://www.debian.org/security/2020/dsa-4673
- https://usn.ubuntu.com/4448-1
- https://security.netapp.com/advisory/ntap-20200327-0005
- https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html
- https://lists.debian.org/debian-lts-announce/2020/03/msg00006.html
- https://lists.apache.org/thread.html/rd547be0c9d821b4b1000a694b8e58ef9f5e2d66db03a31dfe77c4b18@%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rc31cbabb46cdc58bbdd8519a8f64b6236b2635a3922bbeba0f0e3743@%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/ra5dee390ad2d60307b8362505c059cd6a726de4d146d63dfce1e05e7@%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r9ce7918faf347e7aac32be930bf26c233b0b140fe37af0bb294158b6@%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r80e9c8417c77d52c62809168b96912bda70ddf7748f19f8210f745b1@%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r7bc994c965a34876bd94d5ff15b4e1e30b6220a15eb9b47c81915b78@%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/r660cd379afe346f10d72c0eaa8459ccc95d83aff181671b7e9076919@%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r441c1f30a252bf14b07396286f6abd8089ce4240e91323211f1a2d75@%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r127f76181aceffea2bd4711b03c595d0f115f63e020348fe925a916c%40%3Cannounce.tomcat.apache.org%3E
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00025.html
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N- Weakness (CWE)
CWE-444- Platform
- Java / Kotlin (Maven)
- Package
org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat- Disclosed
- 28.02.2020
- Updated
- 11.10.2026 12:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-qxf4-chvg-4r8r - CC BY 4.0
Vulnerability history: org.apache.tomcat:tomcat
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 162
- First → latest
- 12.2018 08.2026
- Without a fix
- 20
- Exploited in attacks
- 1
Severity breakdown
- Critical 8
- High 40
- Medium 102
- Low 12
Disclosures per year
- 2018: 1
- 2019: 1
- 2020: 2
- 2021: 5
- 2022: 125
- 2023: 3
- 2024: 2
- 2025: 4
- 2026: 19
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Potential HTTP request smuggling in Apache Tomcat this entry
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