CVSS 3.1
3.7 lowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:NCVE-2021-43980
Low (3.7). EPSS 2.4% chance of exploitation in the next 30 days. Fixed in org.apache.tomcat:tomcat 10.0.20, 10.1.0-M14, 8.5.78.
The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.
Severity
- EPSS
- 2.4% chance of exploitation in the next 30 days; higher than 83% of CVEs (scores of 2026-10-31)
- CWE
- CWE-362
- Published
- Modified
- Record from
- the NVD, synced
Affected
- apache:tomcat
- debian:debian_linux
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-jx7c-7mj5-9438 | Maven | org.apache.tomcat:tomcat | >=8.5.0 <8.5.78 | 8.5.78 |
| GHSA-jx7c-7mj5-9438 | Maven | org.apache.tomcat:tomcat | >=9.0.0-M1 <9.0.62 | 9.0.62 |
| GHSA-jx7c-7mj5-9438 | Maven | org.apache.tomcat:tomcat | >=10.0.0-M1 <10.0.20 | 10.0.20 |
| GHSA-jx7c-7mj5-9438 | Maven | org.apache.tomcat:tomcat | >=10.1.0-M1 <10.1.0-M14 | 10.1.0-M14 |