{"id":"CVE-2026-77762","title":"Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in Apache Tomcat allows an attacker to inject trailer fields into another HTTP/2 request.\n\n\n\nThis issue affects Apache Tomcat: from…","summary":"Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in Apache Tomcat allows an attacker to inject trailer fields into another HTTP/2 request.\n\n\n\nThis issue affects Apache Tomcat: from…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-362","CWE-821"],"vendor":"Apache Software Foundation","product":"Apache Tomcat","affected":["apache_tomcat >= 11.0.0-M1 <= 11.0.25","apache_tomcat >= 10.1.0-M1 <= 10.1.59","apache_tomcat >= 9.0.39 <= 9.0.121","apache_tomcat >= 8.56.59 <= 8.5.100"],"patched":["hardened_images"],"published":"2026-09-23","updated":"2026-09-30","sourceUpdated":"2026-09-30T15:22:35.070","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-77762","references":[{"url":"https://lists.apache.org/thread/y5r9fvjo7ol24mkoyoc0st8bqrfyqcyn","label":"security@apache.org"},{"url":"http://www.openwall.com/lists/oss-security/2026/09/23/23","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-77762.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-77762"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2539353"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-77762"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77762"},{"url":"https://access.redhat.com/errata/RHSA-2026:68257"},{"url":"https://access.redhat.com/errata/RHSA-2026:68258"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00464,"epssPercentile":0.40023,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-23T15:40:01.556894Z"},"scores":{"nvd":8.1,"vendor":6.5,"adp":8.1},"ingestedAt":"2026-09-23T11:22:32.915Z","slug":"CVE-2026-77762","body":"## Overview\n\nConcurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in Apache Tomcat allows an attacker to inject trailer fields into another HTTP/2 request.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.39 through 9.0.121.\n\n\n\nThe following versions were EOL at the time the CVE was created but are \nknown to be affected: from 8.5.59 through 8.5.100. Other unsupported versions may also be affected.\n\n\n\n\nUsers are recommended to upgrade to version 11.0.26, 10.1.60, 9.0.122, which fix the issue.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:68257** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68257)\n- **RHSA-2026:68258** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68258)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat JBoss Web Server 5, … · updated 2026-09-30 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-77762.json)","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":209767,"id":"CVE-2026-77762","ts":1790180880043,"field":"cvss","old":null,"new":"8.1"},{"seq":209766,"id":"CVE-2026-77762","ts":1790180880043,"field":"severity","old":"none","new":"high"}]}