Symfony: Mailtrap Mailer Webhook Parser Never Verifies the X-Mt-Signature HMAC — Unauthenticated Webhook Event Injection
Priority LOW 36CWE-306Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-306.
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00267 18th percentileScored 2026-11-07
Fix Fixed symfony (symfony): 7.4.12, 8.0.12mailtrap-mailer (/mailtrap-mailer): 7.4.12, 8.0.12+2 more products
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| symfony | symfony | 7.2.0 to before 7.4.12; 8.0.0-BETA1 to before 8.0.12 | 7.4.12, 8.0.12 | Patch available | CNA |
| /mailtrap-mailer | mailtrap-mailer | 7.2.0 to before 7.4.12; 8.0.0-BETA1 to before 8.0.12 | 7.4.12, 8.0.12 | Patch available | CNA |
| — | symfony/mailtrap-mailer (Packagist) | 7.2.0 to before 7.4.12 | 7.4.12 | Patch available | GHSA-59f3-vp2f-mp9w |
| — | symfony/mailtrap-mailer (Packagist) | 8.0.0 to before 8.0.12 | 8.0.12 | Patch available | GHSA-59f3-vp2f-mp9w |
| — | symfony/symfony (Packagist) | 7.2.0 to before 7.4.12 | 7.4.12 | Patch available | GHSA-59f3-vp2f-mp9w |
| — | symfony/symfony (Packagist) | 8.0.0 to before 8.0.12 | 8.0.12 | Patch available | GHSA-59f3-vp2f-mp9w |
- symfony Vendorsymfony Affected 7.2.0 to before 7.4.12; 8.0.0-BETA1 to before 8.0.12 Fixed in 7.4.12, 8.0.12 Patch available CNA
- mailtrap-mailer Vendor/mailtrap-mailer Affected 7.2.0 to before 7.4.12; 8.0.0-BETA1 to before 8.0.12 Fixed in 7.4.12, 8.0.12 Patch available CNA
- symfony/mailtrap-mailer (Packagist) Vendor— Affected 7.2.0 to before 7.4.12 Fixed in 7.4.12 Patch available GHSA-59f3-vp2f-mp9w
- symfony/mailtrap-mailer (Packagist) Vendor— Affected 8.0.0 to before 8.0.12 Fixed in 8.0.12 Patch available GHSA-59f3-vp2f-mp9w
- symfony/symfony (Packagist) Vendor— Affected 7.2.0 to before 7.4.12 Fixed in 7.4.12 Patch available GHSA-59f3-vp2f-mp9w
- symfony/symfony (Packagist) Vendor— Affected 8.0.0 to before 8.0.12 Fixed in 8.0.12 Patch available GHSA-59f3-vp2f-mp9w
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* | 7.2.0 to before 7.4.12; 8.0.0 to before 8.0.12 | Vulnerable | sensiolabs |
- cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* Versions 7.2.0 to before 7.4.12; 8.0.0 to before 8.0.12 Vulnerable ·sensiolabs
Remediation
- Fix · CNA symfony (symfony) Fixed in 7.4.12, 8.0.12
- Fix · CNA mailtrap-mailer (/mailtrap-mailer) Fixed in 7.4.12, 8.0.12
- Fix · GHSA-59f3-vp2f-mp9w symfony/mailtrap-mailer (Packagist) Fixed in 7.4.12 Advisory →
- Fix · GHSA-59f3-vp2f-mp9w symfony/mailtrap-mailer (Packagist) Fixed in 8.0.12 Advisory →
- Fix · GHSA-59f3-vp2f-mp9w symfony/symfony (Packagist) Fixed in 7.4.12 Advisory →
- Fix · GHSA-59f3-vp2f-mp9w symfony/symfony (Packagist) Fixed in 8.0.12 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-45755
- 2026-10-03 Alias added: GHSA-59f3-vp2f-mp9w
References
Patch 2
Other 6
- https://github.com/symfony/symfony/releases/tag/v7.4.12
- https://github.com/symfony/symfony/releases/tag/v8.0.12
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/mailtrap-mailer/CVE-2026-45755.yaml
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45755.yaml
- https://github.com/symfony/symfony
- https://symfony.com/cve-2026-45755
More symfony vulnerabilities
- TI-2024-33775 Ability to change environment from query in symfony/runtime CVSS 3.1HIGH 7.3
- TI-2026-34283 Twig: The `spaceless` filter implicitly marks its output as safe CVSS 4.0MEDIUM 5.1
- TI-2022-07667 Code injection in Twig CVSS 3.1CRITICAL 9.8
- TI-2018-10028 Twig before 2.4.4 allows Server-Side Template Injection (SSTI) via the search search_key… CVSS 3.0CRITICAL 9.8
- TI-2026-35851 Incorrect authorization in symfony CVSS 4.0HIGH 8.7
- TI-2026-35264 Improper input validation in symfony CVSS 4.0HIGH 8.3
Sources
- CVE-2026-45755 · CVE Program
- CVE-2026-45755 · NVD
- FIRST EPSS
- GHSA-59f3-vp2f-mp9w · GitHub Advisory Database · CC BY 4.0
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