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: 0.5% (41st percentile of EPSS-scored CVEs). 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: 0.5%CVSS: 5.3Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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
5.3MEDIUMmedium confidence
EG Risk
55
EG Risk 55/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
41st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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 rangeFix by version rangeDependents
github.com/axllent/mailpit—
  • 1.30.0 up to 1.30.5: fixed in 1.30.5
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 42× 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. 2026-10-04 23:22 UTCEPSS rescore
  2. 2026-10-03 17:04 UTCEG score recompute
  3. 2026-10-03 14:26 UTCEPSS rescore
  4. 2026-10-02 17:56 UTCEPSS rescore
  5. 2026-10-02 14:49 UTCEG score recompute
  6. 2026-10-01 19:50 UTCEPSS rescore
  7. 2026-10-01 12:03 UTCEG score recompute
  8. 2026-09-30 15:03 UTCEPSS rescore
  9. 2026-09-30 09:37 UTCEG score recompute
  10. 2026-09-29 07:20 UTCEG score recompute
  11. 2026-09-28 05:07 UTCEG score recompute
  12. 2026-09-27 13:48 UTCEPSS rescore
  13. 2026-09-27 02:54 UTCEG score recompute
  14. 2026-09-26 15:59 UTCEPSS rescore
  15. 2026-09-25 09:48 UTCEG score recompute
  16. 2026-09-24 07:35 UTCEG score recompute
  17. 2026-09-23 17:54 UTCEPSS rescore
  18. 2026-09-23 05:21 UTCEG score recompute
  19. 2026-09-22 03:07 UTCEG score recompute
  20. 2026-09-21 00:51 UTCEG score recompute
  21. 2026-09-20 20:16 UTCEPSS rescore
  22. 2026-09-19 22:37 UTCEG score recompute
  23. 2026-09-18 20:18 UTCEG score recompute
  24. 2026-09-18 19:28 UTCEPSS rescore
  25. 2026-09-17 21:58 UTCEG score recompute
Show 45 more
  1. 2026-09-16 19:44 UTCEG score recompute
  2. 2026-09-16 14:08 UTCEPSS rescore
  3. 2026-09-16 05:15 UTCEPSS rescore
  4. 2026-09-15 15:22 UTCEG score recompute
  5. 2026-09-14 13:08 UTCEG score recompute
  6. 2026-09-13 10:54 UTCEG score recompute
  7. 2026-09-12 08:40 UTCEG score recompute
  8. 2026-09-11 14:53 UTCEPSS rescore
  9. 2026-09-11 09:37 UTCEPSS rescore
  10. 2026-09-11 06:26 UTCEG score recompute
  11. 2026-09-09 01:53 UTCEG score recompute
  12. 2026-09-08 22:01 UTCEPSS rescore
  13. 2026-09-07 16:01 UTCEPSS rescore
  14. 2026-09-07 06:58 UTCEG score recompute
  15. 2026-09-06 13:47 UTCEPSS rescore
  16. 2026-09-06 04:33 UTCEG score recompute
  17. 2026-09-05 15:31 UTCEPSS rescore
  18. 2026-09-05 02:20 UTCEG score recompute
  19. 2026-09-04 05:07 UTCEPSS rescore
  20. 2026-09-02 21:08 UTCEG score recompute
  21. 2026-09-02 14:12 UTCEPSS rescore
  22. 2026-09-01 16:22 UTCEG score recompute
  23. 2026-09-01 13:54 UTCEPSS rescore
  24. 2026-09-01 04:40 UTCEPSS rescore
  25. 2026-08-31 14:07 UTCEG score recompute
  26. 2026-08-30 19:17 UTCEPSS rescore
  27. 2026-08-30 11:14 UTCEG score recompute
  28. 2026-08-30 01:22 UTCEPSS rescore
  29. 2026-08-29 09:01 UTCEG score recompute
  30. 2026-08-28 21:42 UTCEPSS rescore
  31. 2026-08-28 06:47 UTCEG score recompute
  32. 2026-08-27 04:30 UTCEG score recompute
  33. 2026-08-26 14:47 UTCEPSS rescore
  34. 2026-08-26 02:15 UTCEG score recompute
  35. 2026-08-25 13:49 UTCEPSS rescore
  36. 2026-08-25 00:02 UTCEG score recompute
  37. 2026-08-23 21:48 UTCEG score recompute
  38. 2026-08-23 00:19 UTCEPSS rescore
  39. 2026-08-22 19:35 UTCEG score recompute
  40. 2026-08-21 23:49 UTCEPSS rescore
  41. 2026-08-21 17:21 UTCEG score recompute
  42. 2026-08-21 16:29 UTCEG score recompute
  43. 2026-08-20 22:24 UTCEG score recompute
  44. 2026-08-20 21:32 UTCEG score recompute
  45. 2026-08-20 21:31 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

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 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 0.5% probability of exploitation in the next 30 days (41st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-67447?
CVE-2026-67447 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-67447?
A fix for CVE-2026-67447 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-67447 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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