CVE-2026-11610

389-ds-base: 389-ds-base: heap buffer overflow in sasl_io_recv() via padded sasl unbind

publishedCWE-122

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 sasl_io_recv() in sasl_io.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.

Technical severity8.8 highCVSS 3.1 · CNA: redhat

Published2026-07-07Source updated 2026-11-04

Collected2026-11-042 attributed sources

Fixes and workarounds

Workaround

There is no complete workaround for this flaw. Mitigations that reduce exposure: 1. Restrict network access to LDAP ports (389/636) to trusted networks only. Note: In FreeIPA/IdM deployments, enrolled clients require LDAP access and this may not be practical. 2. If DIGEST-MD5 is not required, disable it via nsslapd-allowed-sasl-mechanisms in cn=config. GSSAPI/Kerberos cannot be disabled in FreeIPA/IdM without breaking domain authentication. 3. Monitor for oversized LDAP UNBIND packets (standard UNBIND is 7 bytes; alert on UNBIND packets exceeding ~100 bytes). 4. Lowering nsslapd-maxbersize reduces maximum overflow size but does not eliminate the vulnerability.

Source: CNA: redhat

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
389-ds-base 389ds `389-ds-base` https://github.com/389ds/389-ds-base	≥ 1.3.2; ≤ 3.3.0 (affected, semver) Other versions: unaffected	CNA: redhat
Red Hat Directory Server 11.5 E4S for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260702180044.0ca98e7e; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 11.7 E4S for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260702180836.f969626e; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 11.9 for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8100020260702145313.37ed7c03; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 12.2 E4S for RHEL 9 Red Hat `redhat-ds:12` https://access.redhat.com/downloads/content/package-browser/	≥ 9020020260703060155.1674d574; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 12.4 E4S for RHEL 9 Red Hat `redhat-ds:12` https://access.redhat.com/downloads/content/package-browser/	≥ 9040020260703055735.1674d574; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 10 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:3.2.0-8.el10_2; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 10.0 Extended Update Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:3.0.6-19.el10_0; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 7 Extended Lifecycle Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:1.3.11.1-13.el7_9; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8 Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8100020260626120929.25e700aa; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8040020260629123121.96015a92; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8040020260629123121.96015a92; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260626130540.824efc52; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260626130540.824efc52; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.8 Telecommunications Update Service Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260630025241.6dbb3803; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260630025241.6dbb3803; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.8.0-8.el9_8; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.2.4-19.el9_2; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.4.5-26.el9_4; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9.6 Extended Update Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.6.1-22.el9_6; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 13.2 Red Hat `dirsrv/dirsrv-container-rhel10` https://catalog.redhat.com/software/containers/	≥ 1783452100; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 12 Red Hat `redhat-ds:12/389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Directory Server 13 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat Enterprise Linux 6 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 8.8 high	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`	CNA: redhat

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://access.redhat.com/errata/RHSA-2026:36195CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36196CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36197CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36198CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36200CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36201CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36202CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36204CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36205CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36206CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36208CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36209CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36585CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36641CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36660CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36670CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36671CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-11610CNA: redhat · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2484414CNA: redhat · issue-tracking, x_refsource_REDHAT

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