{"cve":"CVE-2021-43980","nvd":{"published":"2022-09-28T14:15:09.880","modified":"2026-06-17T04:11:44.097","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","score":3.7},"cwes":["CWE-362"],"references":["http://www.openwall.com/lists/oss-security/2022/09/28/1","https://lists.apache.org/thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3","https://lists.debian.org/debian-lts-announce/2022/10/msg00029.html","https://www.debian.org/security/2022/dsa-5265","http://www.openwall.com/lists/oss-security/2022/09/28/1"],"products":["apache:tomcat","debian:debian_linux"],"source":"nvd","synced_at":"2026-10-19T21:36:05.460296998+00:00"},"epss":{"cve":"CVE-2021-43980","score":0.02362,"percentile":0.83785,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-jx7c-7mj5-9438","url":"https://osv.dev/vulnerability/GHSA-jx7c-7mj5-9438","summary":"Apache Tomcat Race Condition vulnerability","modified":"2024-03-11T16:46:19.307324Z","packages":[{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=8.5.0 <8.5.78"],"fixed":["8.5.78"]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=9.0.0-M1 <9.0.62"],"fixed":["9.0.62"]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=10.0.0-M1 <10.0.20"],"fixed":["10.0.20"]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=10.1.0-M1 <10.1.0-M14"],"fixed":["10.1.0-M14"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}