CVE-2026-11610: 389-ds-base: 389-ds-base: heap buffer overflow in sasl_io_recv() via padded sasl unbind
A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). After a successful SASL bind with integrity protection (SSF > 0), an authenticated attacker can send a specially crafted oversized LDAP UNBIND packet that is copied into a 512-byte heap receive buffer without a bounds check in sasliorecv() in saslio.c. This allows up to approximately 2 megabytes of attacker-controlled data to overflow the buffer, causing a denial of service (server crash). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, any enrolled host, or any service account can trigger this vulnerability over the network after authenticating via GSSAPI. The vulnerable code path has existed since approximately 2013 (389-ds-base 1.3.2) and was not addressed by the CVE-2025-14905 fix, which patched a separate heap overflow in schema.c only.
Other sources
Finding 008 — 389-ds-base SASL heap overflow in sasliorecv().
Vulnerable: ldap/servers/slapd/saslio.c (~line 456), SASLIOBUFFERNOTENCRYPTED path. Introduced by commit b4cdebbe (~2013). Missing bounds check on memcpy into 512-byte cbuffer.
Trigger: SASL bind (GSSAPI/DIGEST-MD5), then send padded raw LDAP UNBIND. DoS confirmed on production binary (389-ds-base-3.1.4-6.fc42).
Fix: add bounds check before memcpy, same pattern as encrypted return path in sasliorecv().
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-11610?
CVE-2026-11610 has a severity rating of high, with a CVSS score of 8.8.
What is the primary risk associated with CVE-2026-11610?
The primary risk of CVE-2026-11610 is a heap buffer overflow that could allow an authenticated attacker to exploit the vulnerability.
How do I fix CVE-2026-11610?
To fix CVE-2026-11610, update the 389 Directory Server (389-ds-base) to the latest version provided by Red Hat or apply the appropriate patches.
Which software is affected by CVE-2026-11610?
CVE-2026-11610 affects the 389 Directory Server (389-ds-base) from the 389 Project and Red Hat.
Can an unauthenticated user exploit CVE-2026-11610?
No, an authenticated user is required to exploit CVE-2026-11610 due to the need for a successful SASL bind.