CVE-2026-45755 json
Symfony: Mailtrap Mailer Webhook Parser Never Verifies the X-Mt-Signature HMAC — Unauthenticated Webhook Event Injection
published 2026-05-28 5 mo ago modified 2026-09-10 1 mo ago also GHSA-59f3-vp2f-mp9w , EUVD-2026-44361
- cvss
- 5.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 18%
- 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 7.4.12 and 8.0.12, MailtrapRequestParser::doParse() received the configured webhook secret but ignored the X-Mt-Signature HMAC header, allowing unauthenticated POST requests to inject forged Mailtrap delivery, bounce, open, click, or spam events. This issue is fixed in versions 7.4.12 and 8.0.12.
Patch / fix
- packagist symfony/mailtrap-mailer 7.4.12, 8.0.12
- packagist symfony/symfony 7.4.12, 8.0.12
- sensiolabs symfony 7.4.12, 8.0.12
- symfony Debian 14 7.4.12+dfsg-1
debian advisories DEBIAN-CVE-2026-45755
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/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/mailtrap-mailer | >=7.2.0, <7.4.12 >=8.0.0, <8.0.12 |
7.4.12 8.0.12 |
| packagist | symfony/symfony | >=7.2.0, <7.4.12 >=8.0.0, <8.0.12 |
7.4.12 8.0.12 |
Affected products
- symfony symfony
- /mailtrap-mailer mailtrap-mailer
Classification
References
-
github.com
/symfony/symfony/commit/4e0467e4e182cf2e704a3d9e1bc1a6be65d52ab8
web, patch
-
github.com
/symfony/symfony/security/advisories/GHSA-59f3-vp2f-mp9w
web, patch, vendor-advisory
-
github.com
/symfony/symfony/releases/tag/v7.4.12
product, release-notes
-
github.com
/symfony/symfony/releases/tag/v8.0.12
product, release-notes
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/mailtrap-mailer/CVE-2026-45755.yaml
web
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45755.yaml
web
-
github.com
/symfony/symfony
package
-
symfony.com
/cve-2026-45755
web
Sources
- CVE List CVE-2026-45755
- GitHub Advisory GHSA-59f3-vp2f-mp9w
- NVD CVE-2026-45755
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.