CVE-2026-45067

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 54% 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: epss, secondary
6.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Description

Symfony\Component\Mime\Address is the value-object every Symfony Mailer address (to/cc/bcc/from/reply-to) flows through; its constructor is documented as validating the address and throwing on invalid input, so developers treat it as a security boundary.

The constructor accepts email addresses whose local-part (the part before @) is an RFC-5322 *quoted string* containing raw \r\n bytes — e.g. "x\r\nBcc: attacker@evil"@example.com. The stored address is later emitted verbatim into (1) the rendered message headers and (2) SmtpTransport's MAIL FROM:<...> / RCPT TO:<...> protocol lines, turning the embedded CRLF into a new mail header and/or a new SMTP command.

Resolution

The Address constructor now rejects addresses containing line breaks.

The patch for this issue is available here for branch 5.4.

Credits

We would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.

CVSS v3
6.3
EG Score
6.3(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity63% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
45.9%
KEV
Not listed

Published

May 27, 2026

Last Modified

July 14, 2026

Advisory Details (1)

Auto-updated Jul 16, 2026
Patch available. Sources: github.
github Patch Available

Email Header / SMTP Command Injection via CRLF in Symfony\Component\Mime\Address · Advisory · symfony/symfony · GitHub

https://github.com/symfony/symfony/security/advisories/GHSA-qpmx-3rfj-7rhv

Vendor Advisories for CVE-2026-45067(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)
PackageVulnerable rangeFixed inDependents
symfony/mimev8.0.0 ... v8.0.9 (7 versions)8.0.12—
symfony/symfonyv8.0.0 ... v8.0.9 (12 versions)8.0.12—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 11× 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.

  1. 2026-07-23 03:16 UTCEG score recompute
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
  6. 2026-07-19 02:29 UTCEPSS rescore
  7. 2026-07-18 10:04 UTCEPSS rescore
  8. 2026-07-16 17:03 UTCEPSS rescore
  9. 2026-07-15 16:57 UTCEPSS rescore
  10. 2026-07-14 18:07 UTCEG score recompute▲ 6.30
  11. 2026-07-14 18:05 UTCMITRE cvelistV5CVSS v3 → 6.3 · CVSS v4 → 6.3 · severity → MEDIUM
  12. 2026-06-14 23:18 UTCEPSS rescore
  13. 2026-06-13 23:00 UTCEPSS rescore
  14. 2026-06-12 23:12 UTCEPSS rescore
  15. 2026-05-27 21:35 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-45067?
CVE-2026-45067 is a medium vulnerability published on May 27, 2026. Description Symfony\Component\Mime\Address is the value-object every Symfony Mailer address (to/cc/bcc/from/reply-to) flows through; its constructor is documented as validating the address and throwing on invalid input, so developers treat it as a security boundary. The constructor accepts email…
When was CVE-2026-45067 disclosed?
CVE-2026-45067 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45067 actively exploited?
CVE-2026-45067 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 45.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-45067?
CVE-2026-45067 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-45067?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45067, 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

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