CVE-2026-67447

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 69% 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
Elevated
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: Elevated riskExposed: 0

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

Mailpit is an email testing tool and API for developers. From 1.30.0 until 1.30.5, Mailpit's internal/smtpd/smtpd.go readData() function calls bufio.Reader.ReadBytes before applying the len(data)+len(line) size check to the completed SMTP DATA line against Server.MaxSize. An unauthenticated SMTP client can send a single line larger than the configured MaxMessageSize, causing the full line to be allocated before Mailpit returns the 552 5.3.4 rejection. This post-fix gap remains after normal multi-line DATA accumulation was bounded, and concurrent oversized lines can create substantial memory pressure beyond the configured message-size cap. This issue is fixed in version 1.30.5.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
55(Attend)
EG Risk 55/100SSVC: Attend

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
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

August 20, 2026

Last Modified

September 18, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

Release v1.30.5 (axllent/mailpit)

Patch available: axllent/mailpit v1.30.5

https://github.com/axllent/mailpit/releases/tag/v1.30.5
github_commit

commit 8720c6bd8281 (axllent/mailpit)

Fix landed in axllent/mailpit commit 8720c6bd8281 — awaiting tagged release

https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98c
github Patch Available🟡 PoC Available

SMTP DATA line reader buffers over-limit input before size enforcement · Advisory · axllent/mailpit · GitHub

https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97

Vendor Advisories for CVE-2026-67447(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/axllent/mailpit—1.30.5—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 48× 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. 2026-09-18 20:18 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 21:58 UTCEG score recompute
  4. 2026-09-16 19:44 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 05:15 UTCEPSS rescore
  7. 2026-09-15 15:22 UTCEG score recompute
  8. 2026-09-14 13:08 UTCEG score recompute
  9. 2026-09-13 10:54 UTCEG score recompute
  10. 2026-09-12 08:40 UTCEG score recompute
  11. 2026-09-11 14:53 UTCEPSS rescore
  12. 2026-09-11 09:37 UTCEPSS rescore
  13. 2026-09-11 06:26 UTCEG score recompute
  14. 2026-09-09 01:53 UTCEG score recompute
  15. 2026-09-08 22:01 UTCEPSS rescore
  16. 2026-09-07 16:01 UTCEPSS rescore
  17. 2026-09-07 06:58 UTCEG score recompute
  18. 2026-09-06 13:47 UTCEPSS rescore
  19. 2026-09-06 04:33 UTCEG score recompute
  20. 2026-09-05 15:31 UTCEPSS rescore
  21. 2026-09-05 02:20 UTCEG score recompute
  22. 2026-09-04 05:07 UTCEPSS rescore
  23. 2026-09-02 21:08 UTCEG score recompute
  24. 2026-09-02 14:12 UTCEPSS rescore
  25. 2026-09-01 16:22 UTCEG score recompute
Show 23 more
  1. 2026-09-01 13:54 UTCEPSS rescore
  2. 2026-09-01 04:40 UTCEPSS rescore
  3. 2026-08-31 14:07 UTCEG score recompute
  4. 2026-08-30 19:17 UTCEPSS rescore
  5. 2026-08-30 11:14 UTCEG score recompute
  6. 2026-08-30 01:22 UTCEPSS rescore
  7. 2026-08-29 09:01 UTCEG score recompute
  8. 2026-08-28 21:42 UTCEPSS rescore
  9. 2026-08-28 06:47 UTCEG score recompute
  10. 2026-08-27 04:30 UTCEG score recompute
  11. 2026-08-26 14:47 UTCEPSS rescore
  12. 2026-08-26 02:15 UTCEG score recompute
  13. 2026-08-25 13:49 UTCEPSS rescore
  14. 2026-08-25 00:02 UTCEG score recompute
  15. 2026-08-23 21:48 UTCEG score recompute
  16. 2026-08-23 00:19 UTCEPSS rescore
  17. 2026-08-22 19:35 UTCEG score recompute
  18. 2026-08-21 23:49 UTCEPSS rescore
  19. 2026-08-21 17:21 UTCEG score recompute
  20. 2026-08-21 16:29 UTCEG score recompute
  21. 2026-08-20 22:24 UTCEG score recompute
  22. 2026-08-20 21:32 UTCEG score recompute
  23. 2026-08-20 21:31 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-67447?
CVE-2026-67447 is a medium vulnerability published on August 20, 2026. Mailpit is an email testing tool and API for developers. From 1.30.0 until 1.30.5, Mailpit's internal/smtpd/smtpd.go readData() function calls bufio.Reader.ReadBytes before applying the len(data)+len(line) size check to the completed SMTP DATA line against Server.MaxSize. An unauthenticated SMTP…
When was CVE-2026-67447 disclosed?
CVE-2026-67447 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-67447 actively exploited?
CVE-2026-67447 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 69.0% of all scored CVEs.
What is the CVSS score of CVE-2026-67447?
CVE-2026-67447 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-67447?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-67447, 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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