CVE-2026-43964
Summary
| CVE | CVE-2026-43964 |
|---|---|
| State | PUBLISHED |
| Assigner | mitre |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-04 19:16:07 UTC |
| Updated | 2026-07-15 02:21:46 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.000520000 probability, percentile 0.163460000 (date 2026-05-12)
Problem Types: CWE-193 | CWE-193 CWE-193 Off-by-one Error | CWE-193 Off-by-one Error
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | [email protected] | Secondary | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Postfix | Postfix | affected 2.3 3.8.16 custom | Not specified |
| CNA | Postfix | Postfix | affected 3.9 3.9.10 custom | Not specified |
| CNA | Postfix | Postfix | affected 3.10 3.10.9 custom | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 10 | unaffected 2:3.8.5-10.el10_2 * rpm | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 8 | unaffected 2:3.5.8-8.el8_10 * rpm | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 9 | unaffected 2:3.5.25-3.el9_8 * rpm | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-43964 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43964.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| www.mail-archive.com/[email protected]/msg00110.html | [email protected] | www.mail-archive.com | Mailing List, Third Party Advisory |
| access.redhat.com/errata/RHSA-2026:25932 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| www.openwall.com/lists/oss-security/2026/05/04/30 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List, Third Party Advisory |
| access.redhat.com/errata/RHSA-2026:26205 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:25930 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-05-04T19:01:26.972Z | Reported to Red Hat. |
| ADP | 2026-05-04T18:10:10.509Z | Made public. |
Solutions
ADP: RHSA-2026:25930: Red Hat Enterprise Linux AppStream (v. 10)
ADP: RHSA-2026:25932: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux BaseOS (v. 8)
ADP: RHSA-2026:26205: Red Hat Enterprise Linux AppStream (v. 9)
Workarounds
ADP: To mitigate this vulnerability, review and adjust the following Postfix configurations: - DNSBL: Remove the $rbl_text variable from the rbl_reply_maps and default_rbl_reply settings to prevent triggers via malicious DNSBL TXT responses. - Policy Servers and Milters: Ensure any connected policy daemons or milters return fully RFC-compliant enhanced status codes. They must not return codes that lack text after the third digit (e.g., they should return 5.7.1 Rejected rather than just 5.7.1). - Access Tables and Content Checks: Audit custom access tables, header_checks, body_checks, and transport_maps (specifically error transports) to confirm that any manually defined rejection messages or status codes include descriptive text following the numeric code.