{"id":"CVE-2026-108082","published":"2026-10-15T15:17:22.583","lastModified":"2026-10-16T16:00:33.533","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to versions 5.4.54, 6.4.46, 7.4.19, and 8.1.7, HeaderUtils::split() parsed header values with a pattern whose token alternative also matched whitespace, followed by a (?<!\\s) lookbehind. A run of whitespace placed before a separator could be divided among the iterations of the enclosing repetition in exponentially many ways, and the engine tried all of them before settling. HeaderBag calls it for the Cache-Control header whenever a Request is built, so any application handling HTTP requests is reachable, with no authentication.\n\n\n\nA single request carrying such a header costs close to a second of CPU (813 ms for a run of 17 spaces in an 8 KB header on PHP 8.5, doubling with each extra space). From 18 spaces on, preg_match_all() gives up at pcre.backtrack_limit and split() returns an empty array, so every directive of the header is silently dropped.\n\n\n\nThis issue affects symfony/http-foundation v4.1.0-BETA1 through v5.4.53, v6.0.0-BETA1 through v6.4.45, v7.0.0-BETA1 through v7.4.18, and v8.0.0-BETA1 through v8.1.6.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":["CWE-1333"],"vendors":[],"products":[],"references":[{"url":"https://github.com/symfony/symfony/pull/66048","tags":[]},{"url":"https://github.com/symfony/symfony/pull/66491","tags":[]},{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-r925-mgvr-h9cc","tags":[]},{"url":"https://symfony.com/blog/cve-2026-108082-redos-in-headerutils-split-reachable-through-the-cache-control-request-header","tags":[]}],"exploitRefs":[{"url":"https://github.com/symfony/symfony/pull/66048","tags":[]},{"url":"https://github.com/symfony/symfony/pull/66491","tags":[]},{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-r925-mgvr-h9cc","tags":[]}],"hasPoc":true,"ai":null}