CVE-2026-33603

MEDIUMNVD 6.86.8—
EchelonGraph scoreMEDIUM confidence

Score 6.8 from GitHub Security Advisory published 2026-05-12. NVD baseline CVSS 6.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.8Exploit: NoneExposed: 0

A fix is available — apply it.

Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. Install fixed version. No publicly available exploits are known.

CVSS v3
6.8
EG Score
6.8(medium)
EG Risk
—
EPSS
12.9%
KEV
Not listed

Published

May 12, 2026

Last Modified

May 18, 2026

Advisory Details (1)

Auto-updated May 18, 2026
No patch confirmed yet.
generic
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntudovecot-submissiond (1:2.4.2+dfsg1-3ubuntu2.1) @ resolute2026-06-28ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 45× 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.

Showing the most recent 100 of 135 total refreshes for this CVE.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 02:29 UTCEPSS rescore
  6. 2026-07-18 10:04 UTCEPSS rescore
  7. 2026-07-16 17:03 UTCEPSS rescore
  8. 2026-07-16 02:19 UTCOSV refresh
  9. 2026-07-15 16:57 UTCEPSS rescore
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 02:00 UTCEPSS rescore
  12. 2026-07-13 22:30 UTCEPSS rescore
  13. 2026-07-13 06:13 UTCEPSS rescore
  14. 2026-07-13 06:13 UTCEPSS rescore
  15. 2026-07-12 05:46 UTCEPSS rescore
  16. 2026-07-11 08:27 UTCEPSS rescore
  17. 2026-07-09 19:10 UTCEPSS rescore
  18. 2026-07-08 15:15 UTCEPSS rescore
  19. 2026-07-07 13:46 UTCEPSS rescore
  20. 2026-07-06 16:27 UTCEPSS rescore
  21. 2026-07-06 16:27 UTCEPSS rescore
  22. 2026-07-06 02:23 UTCEPSS rescore
  23. 2026-07-06 02:23 UTCEPSS rescore
  24. 2026-07-05 02:30 UTCEPSS rescore
  25. 2026-07-04 06:31 UTCEPSS rescore
Show 75 more
  1. 2026-07-01 15:06 UTCEPSS rescore
  2. 2026-06-30 23:22 UTCEPSS rescore
  3. 2026-06-29 14:06 UTCEPSS rescore
  4. 2026-06-29 14:06 UTCEPSS rescore
  5. 2026-06-28 14:07 UTCEPSS rescore
  6. 2026-06-28 14:07 UTCEPSS rescore
  7. 2026-06-28 04:56 UTCEPSS rescore
  8. 2026-06-28 04:56 UTCEPSS rescore
  9. 2026-06-28 02:25 UTCVendor advisory
  10. 2026-06-28 02:25 UTCGHSA enrichment
  11. 2026-06-27 03:08 UTCEPSS rescore
  12. 2026-06-26 22:07 UTCVendor advisory
  13. 2026-06-26 22:07 UTCGHSA enrichment
  14. 2026-06-25 23:27 UTCVendor advisory
  15. 2026-06-25 23:27 UTCGHSA enrichment
  16. 2026-06-25 13:49 UTCEPSS rescore
  17. 2026-06-25 13:49 UTCEPSS rescore
  18. 2026-06-24 14:05 UTCEPSS rescore
  19. 2026-06-23 21:33 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
  21. 2026-06-22 14:25 UTCEPSS rescore
  22. 2026-06-22 14:25 UTCEPSS rescore
  23. 2026-06-21 14:56 UTCEPSS rescore
  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 01:59 UTCEPSS rescore
  26. 2026-06-19 19:25 UTCEPSS rescore
  27. 2026-06-19 19:25 UTCEPSS rescore
  28. 2026-06-18 17:52 UTCEPSS rescore
  29. 2026-06-18 17:52 UTCEPSS rescore
  30. 2026-06-17 17:53 UTCEPSS rescore
  31. 2026-06-17 05:30 UTCVendor advisory
  32. 2026-06-17 05:30 UTCGHSA enrichment
  33. 2026-06-16 17:52 UTCEPSS rescore
  34. 2026-06-16 06:49 UTCVendor advisory
  35. 2026-06-16 06:49 UTCGHSA enrichment
  36. 2026-06-15 17:49 UTCEPSS rescore
  37. 2026-06-14 23:46 UTCVendor advisory
  38. 2026-06-14 23:45 UTCGHSA enrichment
  39. 2026-06-14 23:18 UTCEPSS rescore
  40. 2026-06-14 01:05 UTCVendor advisory
  41. 2026-06-14 01:05 UTCGHSA enrichment
  42. 2026-06-13 23:00 UTCEPSS rescore
  43. 2026-06-12 23:12 UTCEPSS rescore
  44. 2026-06-12 23:12 UTCEPSS rescore
  45. 2026-06-12 17:02 UTCVendor advisory
  46. 2026-06-12 17:02 UTCGHSA enrichment
  47. 2026-06-11 16:57 UTCVendor advisory
  48. 2026-06-11 16:57 UTCGHSA enrichment
  49. 2026-06-11 14:00 UTCEPSS rescore
  50. 2026-06-10 22:18 UTCEPSS rescore
  51. 2026-06-10 17:38 UTCVendor advisory
  52. 2026-06-10 17:38 UTCGHSA enrichment
  53. 2026-06-10 13:22 UTCEPSS rescore
  54. 2026-06-09 18:58 UTCVendor advisory
  55. 2026-06-09 18:58 UTCGHSA enrichment
  56. 2026-06-08 20:18 UTCVendor advisory
  57. 2026-06-08 20:18 UTCGHSA enrichment
  58. 2026-06-08 14:17 UTCEPSS rescore
  59. 2026-06-08 14:17 UTCEPSS rescore
  60. 2026-06-07 21:27 UTCVendor advisory
  61. 2026-06-07 21:26 UTCGHSA enrichment
  62. 2026-06-07 15:25 UTCEPSS rescore
  63. 2026-06-07 15:25 UTCEPSS rescore
  64. 2026-06-07 15:25 UTCEPSS rescore
  65. 2026-06-06 22:47 UTCVendor advisory
  66. 2026-06-06 22:47 UTCGHSA enrichment
  67. 2026-06-06 13:47 UTCEPSS rescore
  68. 2026-06-06 13:47 UTCEPSS rescore
  69. 2026-06-06 00:06 UTCVendor advisory
  70. 2026-06-06 00:06 UTCGHSA enrichment
  71. 2026-06-05 22:47 UTCEPSS rescore
  72. 2026-06-05 22:47 UTCEPSS rescore
  73. 2026-06-05 06:10 UTCEPSS rescore
  74. 2026-06-05 06:10 UTCEPSS rescore
  75. 2026-06-05 01:27 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-33603?
CVE-2026-33603 is a medium vulnerability published on May 12, 2026. Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and…
When was CVE-2026-33603 disclosed?
CVE-2026-33603 was first published in the National Vulnerability Database on May 12, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33603 actively exploited?
CVE-2026-33603 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 12.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-33603?
CVE-2026-33603 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2026-33603?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33603, 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.

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