CVE-2026-34933
Avahi ≤ 0.9
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-34933 is a medium-severity Reachable Assertion (CWE-617) vulnerability in Avahi Avahi. Its CVSS base score is 5.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 10th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18910
Vulnerability Data
Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. Prior to version 0.9-rc4, any unprivileged local user can crash avahi-daemon by sending a single D-Bus method call with conflicting publish flags. This…
more
issue has been patched in version 0.9-rc4.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local unprivileged crash of avahi-daemon via reachable assertion in D-Bus handler directly enables application exploitation for endpoint DoS.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly prevents the malformed D-Bus publish-flag combination from reaching the assertion in avahi-daemon.
Enforces fine-grained authorization on D-Bus method calls so unprivileged users cannot invoke the crashing publish interface.
Requires prompt application of the vendor patch that removes the reachable assertion (0.9-rc4).
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 prevent unsafe assertions from being coded in reachable paths.
Runtime monitoring of software can detect assertion-triggered crashes as adverse events.
Vulnerability identification processes can discover and record reachable-assertion flaws before deployment.
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 in development can detect reachable assertions before release, reducing the likelihood of exploitation.
Secure development lifecycle mandates defensive coding and input validation that prevent reachable assertions from being triggered by untrusted data.
Application security requirements can specify that assertions must not be reachable from attacker-controlled inputs.
Secure architecture principles discourage the use of assertions for runtime error handling that an attacker could exploit.
Secure coding standards explicitly ban the use of assert() or equivalent statements that can be triggered by external input.