---
id: CVE-2026-16560
title: >-
  389-ds-base: 389-ds-base: heap-buffer-overflow in rdn_av_swap on quoted
  multivalued rdn
summary: >-
  A heap-buffer-overflow flaw was found in Directory Server (389-ds-base). When
  a DN contains a legacy-quoted value, the server won't close the heap
  allocation allowing another call to refer to the same memory pointer causing a
  denial of s…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-1220
vendor: Red Hat
product: 'redhat-ds:11/389-ds-base'
affected:
  - 'redhat-ds:11/389-ds-base (all versions)'
  - 'redhat-ds:12/389-ds-base (all versions)'
  - 389-ds-base (all versions)
  - 389-ds-base (all versions)
  - 389-ds-base (all versions)
  - 389-ds-base (all versions)
  - 389-ds-base (all versions)
  - 389-ds-base (all versions)
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-07-22T18:01:40.896935Z'
published: '2026-07-22'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T19:24:06.831Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-16560'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-16560'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2506102'
    label: RHBZ#2506102
tags:
  - cve.org
epss: 0.00396
epssPercentile: 0.33993
ingestedAt: '2026-11-05T22:38:31.535Z'
---

## Overview

A heap-buffer-overflow flaw was found in Directory Server (389-ds-base). When a DN contains a legacy-quoted value, the server won't close the heap allocation allowing another call to refer to the same memory pointer causing a denial of service or an arbitrary memory write operation.

## Affected

- `redhat-ds:11/389-ds-base (all versions)`
- `redhat-ds:12/389-ds-base (all versions)`
- `389-ds-base (all versions)`
- `389-ds-base (all versions)`
- `389-ds-base (all versions)`
- `389-ds-base (all versions)`
- `389-ds-base (all versions)`
- `389-ds-base (all versions)`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

### Workarounds

Denial of service is more reliably observed
when heap debugging is enabled (for example AddressSanitizer or MALLOC_CHECK_=3),
or depending on heap layout and subsequent memory allocator activity. For this
reason Red Hat rates availability impact as Low (A:L) rather than High.
There is no configuration switch to disable DN normalization for client-supplied DNs.
The vulnerable code path is present in all currently supported 389-ds-base versions
that ship the quoted-RDN parsing logic in dn.c.