Is CVE-2026-43964 in the CISA KEV catalog?

No. CVE-2026-43964 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-43964?

CVE-2026-43964 has a CVSS v3 base score of 3.7 (Low).

What is the EPSS score for CVE-2026-43964?

CVE-2026-43964 has an EPSS score of 0.41% (33th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-43964?

Upgrade postfix on debian unstable to 3.11.2-1 or later. Fixes are available for 38 affected products.

CVE & CISA-KEV Catalog

CVE-2026-43964

LOW

3.7

CVSS v3

NVD

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.

CWE-193

How to fix

Remediation Available

postfixDebian

Fixed in:3.11.2-1CVE-2026-43964

postfixRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfixRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-cdbRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-cdbRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-cdb-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-cdb-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-debugsourceRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-debugsourceRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-ldapRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-ldapRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-ldap-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-ldap-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-lmdbRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-lmdbRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-lmdb-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-lmdb-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-mysqlRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-mysqlRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-mysql-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-mysql-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pcreRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pcreRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pcre-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pcre-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-perl-scriptsRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-perl-scriptsRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pgsqlRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pgsqlRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pgsql-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-pgsql-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-sqliteRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-sqliteRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-sqlite-debuginfoRed Hat / RHEL

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfix-sqlite-debuginfoRocky

Fixed in:2:3.8.5-10.el10_2RHSA-2026:25930

Fixed in:2:3.5.8-8.el8_10RHSA-2026:25932

Fixed in:2:3.5.25-3.el9_8RHSA-2026:26205

postfixUbuntu

Fixed in:2.11.0-1ubuntu1.2+esm4USN-8253-2

Fixed in:3.1.0-3ubuntu0.4+esm4USN-8253-2

Fixed in:3.3.0-1ubuntu0.4+esm4USN-8253-2

Fixed in:3.4.13-0ubuntu1.4+esm1USN-8253-2

Fixed in:3.6.4-1ubuntu1.4USN-8253-1

Fixed in:3.8.6-1ubuntu0.1USN-8253-1

Fixed in:3.10.2-1ubuntu2.1USN-8253-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.41%probability of exploitation in 30 days

33rdpercentile

Low risk: more likely to be exploited than 33% of all known CVEs.

References

Third-Party Advisory2

Other references6

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.