CVE-2026-33603
Dovecot ≤ 2.4.4
Raw vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-33603 is a medium-severity Resource Injection (CWE-99) vulnerability in Dovecot Dovecot. Its CVSS base score is 6.8 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 12th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-3 (Access Enforcement) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-29468
Vulnerability Data
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…
more
communications between Dovecot and client as MITM proxy. Install fixed version. No publicly available exploits are known.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.8V1.3.9V1.3.11V9.2.2
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of inputs before they are accepted as resource identifiers.
Enforces authorizations on resource access so an injected identifier cannot reach outside the intended sphere.
Enforces information flow rules that block use of untrusted identifiers to reach unauthorized resources.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input validation and sanitization that prevent resource-identifier injection flaws.
Least-privilege access policy and enforcement limits damage from injected resource identifiers even when input validation is absent.
Network segmentation and unauthorized-access controls reduce the blast radius of successful resource injection.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect resource-injection flaws but does not itself implement preventive controls.
Secure SDLC mandates input validation and resource-identifier sanitization that directly prevents resource injection.
Application security requirements explicitly call for controls on external identifiers used to access resources.
Secure architecture principles reduce attack surface for resource injection but do not prescribe identifier validation.
Secure coding standards require strict validation and whitelisting of all resource identifiers before use.
Information-access-restriction policies limit which resources can be referenced, indirectly reducing injection impact.