{"id":"CVE-2026-48747","aliases":["GHSA-rrj9-5q2j-4gvr"],"url":"https://o3.security/vulnerability/CVE-2026-48747","summary":"Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade","details":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 7.4.13 and 8.0.13, MailomatRequestParser::validateSignature() parsed X-MOM-Webhook-Signature as algo=signature and passed the request-selected algorithm to hash_hmac(), allowing a signature algorithm downgrade instead of enforcing Mailomat's documented SHA-256 webhook signature. This issue is fixed in versions 7.4.13 and 8.0.13.","published":"2026-07-14T19:16:24.327Z","modified":"2026-08-12T03:51:44.323291011Z","cvss":null,"epss":{"score":0.00197,"percentile":0.09799,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"symfony/mailomat-mailer","fixedVersion":"7.4.13"},{"ecosystem":"Packagist","name":"symfony/mailomat-mailer","fixedVersion":"8.0.13"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"7.4.13"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"8.0.13"}],"fix":{"url":"https://github.com/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88","label":"symfony/symfony@bdfe9fe"},"references":[{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v7.4.13"},{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v8.0.13"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48747.json"},{"type":"ADVISORY","url":"https://github.com/symfony/symfony/security/advisories/GHSA-rrj9-5q2j-4gvr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48747"},{"type":"FIX","url":"https://github.com/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:44.323291011Z"}}