CVE-2026-48747 json
Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade
published 2026-06-15 4 mo ago modified 2026-09-10 1 mo ago also GHSA-rrj9-5q2j-4gvr , EUVD-2026-44375
- cvss
- 5.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 16%
- public exploits
- 0
- none known
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.
Patch / fix
- packagist symfony/mailomat-mailer 7.4.13, 8.0.13
- packagist symfony/symfony 7.4.13, 8.0.13
- sensiolabs symfony 7.4.13, 8.0.13
- symfony Debian 14 7.4.13+dfsg-1
debian advisories DEBIAN-CVE-2026-48747
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.3 | 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 |
| CNA | 4.0 | 6.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | symfony/mailomat-mailer | >=7.2.0, <7.4.13 >=8.0.0, <8.0.13 |
7.4.13 8.0.13 |
| packagist | symfony/symfony | >=7.2.0, <7.4.13 >=8.0.0, <8.0.13 |
7.4.13 8.0.13 |
Affected products
- symfony symfony
- symfony mailomat-mailer
Classification
References
-
github.com
/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88
web, patch
-
github.com
/symfony/symfony/security/advisories/GHSA-rrj9-5q2j-4gvr
web, patch, vendor-advisory
-
github.com
/symfony/symfony/releases/tag/v7.4.13
product, release-notes
-
github.com
/symfony/symfony/releases/tag/v8.0.13
product, release-notes
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/mailomat-mailer/CVE-2026-48747.yaml
web
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-48747.yaml
web
-
github.com
/symfony/symfony
package
-
symfony.com
/cve-2026-48747
web
Sources
- CVE List CVE-2026-48747
- GitHub Advisory GHSA-rrj9-5q2j-4gvr
- NVD CVE-2026-48747
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