CVE-2026-43964

LOW

Published May 4, 2026 Modified May 11, 2026 CWE-193

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.

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CVSS v3.1 Score

3.7

LOW

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

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-193 CWE-193

Affected Products

Vendor	Product	Versions
postfix	postfix	< 3.8.16
postfix	postfix	3.9.0 — 3.9.10
postfix	postfix	3.10.0 — 3.10.9

References

Other References

https://www.mail-archive.com/[email protected]/msg00110.html http://www.openwall.com/lists/oss-security/2026/05/04/30

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 3.7 (LOW).

How severe is CVE-2026-43964? +

CVE-2026-43964 has a CVSS v3.1 score of 3.7 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43964? +

CVE-2026-43964 affects products from postfix, specifically: postfix. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43964? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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