6.8

CVE-2026-33603: dovecot Resource Injection

CVSS: 6.8v3.1MediumAnalyzed
AliasesALPINE-CVE-2026-33603UBUNTU-CVE-2026-33603DEBIAN-CVE-2026-33603
Published 12-05-2026Last modified 12-05-2026
Open JSON

Vulnerability summary

CVE-2026-33603 is a medium (CVSS 6.8) Resource Injection vulnerability in dovecot. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.3% of scored vulnerabilities.

Overall risk
27/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.8/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 5 · Related 6
OPENSUSE-SU-2026:10766-1OPENSUSE-SU-2026:21109-1SUSE-SU-2026:22185-1SUSE-SU-2026:2645-1SUSE-SU-2026:4139-1USN-8365-1

Timeline

  1. 12-05-2026
    PublishedVulnerability first disclosed.
  2. 12-05-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

+0.02 pp

From 0.21% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.23%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Alpine1 product
  • dovecot< 2.4.4-r0
Debian1 product
  • dovecot< 1:2.3.19.1+dfsg1-2.1+deb12u6 | < 1:2.4.1+dfsg1-6+deb13u6 | < 1:2.4.4+dfsg1-1
Dovecot1 product
Open-xchange1 product
Open-xchange gmbh1 product
Ubuntu1 product
  • dovecotAll versions (No fix recorded) | < 1:2.3.16+dfsg1-3ubuntu2.9 | < 1:2.3.21+dfsg1-2ubuntu6.5 | < 1:2.4.1+dfsg1-5ubuntu4.2 | < 1:2.4.2+dfsg1-3ubuntu2.1

6 vendors · 6 products

References

7 links