Medium
Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-48747
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 14:09 UTC · Revision 1
Source evidence
Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade
core-osv · Original sourcePublished 14 Jul 2026, 19:16 UTC
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.
osv:CVE-2026-48747
Complete source record
{
"id": "6bdc99e292662f64d808ad66972a4db84d30d9d6f9277b935cdaccac011f166c",
"url": "https://osv.dev/vulnerability/CVE-2026-48747",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade",
"summary": "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.",
"evidence": "osv:CVE-2026-48747",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-48747",
"aliases": [
"CVE-2026-48747",
"GHSA-rrj9-5q2j-4gvr"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/symfony/security-http",
"type": "GIT",
"events": [
{
"introduced": "0d0ab4d491f22306c893b2d30ce73ea911201a61"
},
{
"fixed": "da3c28025a664e6a88e1af104a74457d99301161"
},
{
"introduced": "bea6dc79db4d95c34b77ec27273d812aa64d65be"
},
{
"fixed": "ca895c1303cc1d290f190cd7301d48fcef9e73e5"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "7.2.0"
},
{
"fixed": "7.4.13"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "8.0.0"
},
{
"fixed": "8.0.13"
}
],
"source": "CPE_RANGE"
}
]
}
},
{
"repo": "https://github.com/symfony/symfony",
"type": "GIT",
"events": [
{
"introduced": "df8cd437bf489cf5aebe7e01e61daad120321c3b"
},
{
"fixed": "d9981b6e4c77b97472845a9b7fcba5507208aacc"
},
{
"introduced": "2e913a829cfbbf9cb38b321bdff1806b44b192eb"
},
{
"fixed": "ad82cb517407582bb697e079c5ee62bf8b7af3b7"
},
{
"fixed": "bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "7.2.0"
},
{
"fixed": "7.4.13"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "8.0.0"
},
{
"fixed": "8.0.13"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "d9981b6e4c77b97472845a9b7fcba5507208aacc"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v7.4.13"
},
{
"range": [
{
"fixed": "ad82cb517407582bb697e079c5ee62bf8b7af3b7"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v8.0.13"
}
]
}
}
],
"versions": [
"v8.0.12",
"v7.4.12",
"v8.0.11",
"v7.4.11",
"v7.4.0-BETA1",
"v8.0.9",
"v7.4.9",
"v8.0.8",
"v7.4.8",
"v8.0.6",
"v7.4.6",
"v8.0.4",
"v7.4.4",
"v8.0.3",
"v7.4.3",
"v8.0.1",
"v7.4.1",
"v7.4.0",
"v8.0.0",
"v7.4.0-RC2",
"v7.4.0-RC1",
"v7.3.0",
"v7.3.0-RC1",
"v7.3.0-BETA2",
"v7.3.0-BETA1",
"v7.2.1",
"v7.2.0-RC1",
"v7.2.0",
"v8.0.10",
"v8.0.7",
"v8.0.5",
"v8.0.2"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48747.json"
}
}
],
"modified": "2026-10-28T02:30:36.048254597Z",
"provider": "osv",
"references": [
"https://github.com/symfony/symfony/releases/tag/v7.4.13",
"https://github.com/symfony/symfony/releases/tag/v8.0.13",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48747.json",
"https://github.com/symfony/symfony/security/advisories/GHSA-rrj9-5q2j-4gvr",
"https://nvd.nist.gov/vuln/detail/CVE-2026-48747",
"https://github.com/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88"
],
"provider_metadata": {
"cwe_ids": [
"CWE-347",
"CWE-757"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48747.json"
}
},
"related_cves": [
{
"value": "CVE-2026-48747",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 503485,
"published_at": "2026-07-14T19:16:24.327+00:00"
}