CVE-2026-14940: directory server Heap Overflow — Fix

Description

A heap-buffer-overflow flaw was found in 389 Directory Server (389-ds-base). When normalizing a Distinguished Name (DN) that contains a legacy-quoted value encoding a multivalued nested Relative Distinguished Name (RDN), the server can write past the end of a heap allocation while sorting RDN attribute-value pairs. An unauthenticated remote attacker can trigger this condition by sending an LDAP operation whose DN reaches the DN normalization routine, such as a search with a crafted base DN. This can corrupt heap memory and may cause denial of service.

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CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0029

Probability of exploitation

0.22%

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-122 CWE-122

Affected Products

Vendor	Product	Versions
redhat	directory_server	All
redhat	directory_server	All
redhat	directory_server	All
redhat	389_directory_server	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All

References

Advisories & Patches

https://access.redhat.com/security/cve/CVE-2026-14940 https://bugzilla.redhat.com/show_bug.cgi?id=2497697

Frequently Asked Questions

What is CVE-2026-14940? +

A heap-buffer-overflow flaw was found in 389 Directory Server (389-ds-base). When normalizing a Distinguished Name (DN) that contains a legacy-quoted value encoding a multivalued nested Relative Distinguished Name (RDN), the server can write past the end of a heap allocation while sorting RDN attribute-value pairs. An unauthenticated remote attacker can trigger this condition by sending an LDAP operation whose DN reaches the DN normalization routine, such as a search with a crafted base DN. This can corrupt heap memory and may cause denial of service. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-14940? +

CVE-2026-14940 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0029, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-14940? +

CVE-2026-14940 affects products from redhat, specifically: 389_directory_server, directory_server, enterprise_linux. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-14940? +

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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