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.
CVE-2026-45755
MEDIUMNVD 5.36.9Trending — 4 sources updated this week
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 6.9 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.0%, top 92% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: cna:github_m, epss
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 6.9(low)
- EPSS
- 22.2%
- KEV
- Not listed
Published
May 28, 2026
Last Modified
July 15, 2026
Advisory Details (4)
Auto-updated Jul 15, 2026Patch available. Sources: github_commit, github_release, github.
github Patch Available
Mailtrap Mailer Webhook Parser Never Verifies the X-Mt-Signature HMAC: Unauthenticated Webhook Event Injection · Advisory · symfony/symfony · GitHub
https://github.com/symfony/symfony/security/advisories/GHSA-59f3-vp2f-mp9wgithub_release Patch Available
v8.0.12
Patch available: symfony/symfony v8.0.12
https://github.com/symfony/symfony/releases/tag/v8.0.12github_release Patch Available
v7.4.12
Patch available: symfony/symfony v7.4.12
https://github.com/symfony/symfony/releases/tag/v7.4.12github_commit Patch Available
commit 4e0467e4e182 (symfony/symfony)
Patch available: symfony/symfony v7.4.12 (contains commit 4e0467e4e182)
https://github.com/symfony/symfony/commit/4e0467e4e182cf2e704a3d9e1bc1a6be65d52ab8Vendor Advisories for CVE-2026-45755(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(2 across 1 ecosystem)
Packagist(2)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| symfony/mailtrap-mailer | v8.0.0 | 8.0.12 | — |
| symfony/symfony | v8.0.0 ... v8.0.9 (12 versions) | 8.0.12 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 14:22 UTCNVD updateCVSS v3 → 5.3
- 2026-07-14 19:03 UTCEG score recompute▲ 6.90
- 2026-07-14 19:00 UTCMITRE cvelistV5CVSS v3 → 6.9 · CVSS v4 → 6.9
- 2026-06-15 16:30 UTCEG score recompute
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-05-28 18:06 UTCEG score recompute
Related CVEs(same CWE)
Same CWE
10 shownCWE-306 · CWE-347
Frequently asked(5)
What is CVE-2026-45755?
CVE-2026-45755 is a medium vulnerability published on May 28, 2026. 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…
When was CVE-2026-45755 disclosed?
CVE-2026-45755 was first published in the National Vulnerability Database on May 28, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45755 actively exploited?
CVE-2026-45755 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 22.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-45755?
CVE-2026-45755 has a CVSS v3 base score of 5.3 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 6.9. The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-45755?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45755, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-45755
Is Your Infrastructure Affected by CVE-2026-45755?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.