CVE-2026-33604

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreHIGH confidence

Score 5.9 from GitHub Security Advisory published 2026-08-28. a secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

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

An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injection of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. No publicly available exploits are known.

CVSS v3
5.9
EG Score
5.9(high)
EG Risk
27(Track)
EG Risk 27/100SSVC: 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
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

August 28, 2026

Last Modified

September 3, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
No patch confirmed yet.
generic
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json

Vendor Advisories for CVE-2026-33604(1)

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

Affected Packages

(5 across 5 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
dovecot—2.4.5-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
dovecot—2.4.5-r0—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
dovecot1:2.3.19.1+dfsg1-2.1 ... 1:2.4.5+dfsg1-2 (42 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
dovecot1:2.4.1+dfsg1-6 ... 1:2.4.5+dfsg1-2 (20 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
dovecot1:2.4.1+dfsg1-6 ... 1:2.4.5+dfsg1-2 (14 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 69× 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 19:28 UTCEPSS rescore
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 11:02 UTCEG score recompute
  4. 2026-09-18 11:02 UTCGHSA enrichment
  5. 2026-09-17 19:30 UTCEPSS rescore
  6. 2026-09-17 13:04 UTCGHSA enrichment
  7. 2026-09-16 14:42 UTCEG score recompute
  8. 2026-09-16 14:42 UTCGHSA enrichment
  9. 2026-09-16 14:08 UTCEPSS rescore
  10. 2026-09-16 05:15 UTCEPSS rescore
  11. 2026-09-15 16:44 UTCEG score recompute
  12. 2026-09-15 16:44 UTCGHSA enrichment
  13. 2026-09-15 03:11 UTCEPSS rescore
  14. 2026-09-14 18:46 UTCGHSA enrichment
  15. 2026-09-13 20:04 UTCEG score recompute
  16. 2026-09-13 20:04 UTCGHSA enrichment
  17. 2026-09-13 16:47 UTCEPSS rescore
  18. 2026-09-12 22:06 UTCEG score recompute
  19. 2026-09-12 22:06 UTCGHSA enrichment
  20. 2026-09-12 15:01 UTCEPSS rescore
  21. 2026-09-12 00:08 UTCEG score recompute
  22. 2026-09-12 00:07 UTCGHSA enrichment
  23. 2026-09-11 14:53 UTCEPSS rescore
  24. 2026-09-11 09:37 UTCEPSS rescore
  25. 2026-09-11 02:09 UTCEG score recompute
Show 44 more
  1. 2026-09-11 02:09 UTCGHSA enrichment
  2. 2026-09-10 09:34 UTCEPSS rescore
  3. 2026-09-10 04:11 UTCGHSA enrichment
  4. 2026-09-09 06:13 UTCEG score recompute
  5. 2026-09-09 06:13 UTCGHSA enrichment
  6. 2026-09-08 22:00 UTCEPSS rescore
  7. 2026-09-08 08:16 UTCEG score recompute
  8. 2026-09-08 08:16 UTCGHSA enrichment
  9. 2026-09-07 16:01 UTCEPSS rescore
  10. 2026-09-07 10:18 UTCEG score recompute
  11. 2026-09-07 10:17 UTCGHSA enrichment
  12. 2026-09-06 13:47 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-06 12:17 UTCEG score recompute
  15. 2026-09-06 12:17 UTCGHSA enrichment
  16. 2026-09-05 14:19 UTCGHSA enrichment
  17. 2026-09-04 16:22 UTCEG score recompute
  18. 2026-09-04 16:21 UTCGHSA enrichment
  19. 2026-09-04 05:06 UTCEPSS rescore
  20. 2026-09-03 18:22 UTCGHSA enrichment
  21. 2026-09-03 08:25 UTCEG score recompute
  22. 2026-09-03 08:25 UTCGHSA enrichment
  23. 2026-09-02 14:11 UTCEPSS rescore
  24. 2026-09-02 10:27 UTCEG score recompute
  25. 2026-09-02 10:27 UTCGHSA enrichment
  26. 2026-09-01 13:53 UTCEPSS rescore
  27. 2026-09-01 12:25 UTCEG score recompute
  28. 2026-09-01 12:25 UTCGHSA enrichment
  29. 2026-09-01 04:39 UTCEPSS rescore
  30. 2026-09-01 04:39 UTCEPSS rescore
  31. 2026-08-31 14:21 UTCEG score recompute
  32. 2026-08-31 14:20 UTCGHSA enrichment
  33. 2026-08-30 19:17 UTCEPSS rescore
  34. 2026-08-30 16:19 UTCEG score recompute
  35. 2026-08-30 16:19 UTCGHSA enrichment
  36. 2026-08-30 01:22 UTCEPSS rescore
  37. 2026-08-29 18:21 UTCGHSA enrichment
  38. 2026-08-28 20:21 UTCEG score recompute
  39. 2026-08-28 20:21 UTCGHSA enrichment
  40. 2026-08-28 19:45 UTCEG score recompute
  41. 2026-08-28 19:45 UTCGHSA enrichment
  42. 2026-08-28 12:23 UTCEG score recompute
  43. 2026-08-28 11:25 UTCEG score recompute
  44. 2026-08-28 11:19 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-33604?
CVE-2026-33604 is a medium vulnerability published on August 28, 2026. An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that…
When was CVE-2026-33604 disclosed?
CVE-2026-33604 was first published in the National Vulnerability Database on August 28, 2026, with the most recent update on September 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33604 actively exploited?
CVE-2026-33604 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 80.6% of all scored CVEs.
What is the CVSS score of CVE-2026-33604?
CVE-2026-33604 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-33604?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33604, 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-2026-33604

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