CVE-2026-43964
Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.51%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.51% probability · 43th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-193
- Affected
- postfix/postfix
- Source
- cve@mitre.org
EPSS 0.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://www.mail-archive.com/postfix-announce@postfix.org/msg00110.htmlMailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/05/04/30Mailing List, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:25930
- https://access.redhat.com/errata/RHSA-2026:25932
- https://access.redhat.com/errata/RHSA-2026:26205
- https://access.redhat.com/errata/RHSA-2026:50963
- https://access.redhat.com/errata/RHSA-2026:50964
- https://access.redhat.com/errata/RHSA-2026:51034
- https://access.redhat.com/errata/RHSA-2026:51436
- https://access.redhat.com/errata/RHSA-2026:57174
- https://access.redhat.com/security/cve/CVE-2026-43964
- https://bugzilla.redhat.com/show_bug.cgi?id=2466488
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43964.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.