CVE-2026-48747 Details
Description
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.
A vulnerability exists in the Symfony Mailer component's Mailomat webhook signature validation. The issue is present in Symfony versions 7.2 through 7.4.12 and 8.0 prior to 8.0.13. The vulnerability arises because the validation method parses the 'X-MOM-Webhook-Signature' header and allows the signature algorithm to be downgraded by passing the wire-supplied algorithm to the 'hash_hmac()' function. This could lead to the acceptance of weaker signature algorithms instead of enforcing Mailomat's required SHA-256 signature. The vulnerability could be exploited if an attacker can compute a signature using a less secure algorithm and send it in the webhook request.
Users can upgrade to Symfony versions 7.4.13 or 8.0.13, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 15, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88 | [email protected] | Patch |
| https://github.com/symfony/symfony/releases/tag/v7.4.13 | [email protected] | ProductRelease Notes |
| https://github.com/symfony/symfony/releases/tag/v8.0.13 | [email protected] | ProductRelease Notes |
| https://github.com/symfony/symfony/security/advisories/GHSA-rrj9-5q2j-4gvr | [email protected] | PatchVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-347 | Improper Verification of Cryptographic Signature | [email protected] |
| CWE-757 | Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| sensiolabs symfony | >= 7.2.0, < 7.4.13 >= 8.0.0, < 8.0.13 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 15, 2026 | Initial Analysis | [email protected] |
| Jul 14, 2026 | New CVE Received | [email protected] |