# CVE-2026-11791: 389-ds-base: 389-ds-base: use-after-free in schema reload via attr_syntax_swap_ht()

Status: published. Published: 2026-06-18. Updated: 2026-11-07.

A flaw was found in 389 Directory Server. During schema reload, the attr_syntax_swap_ht() function unconditionally frees attribute syntax information nodes, bypassing the refcount-based deferred deletion used elsewhere in the attribute syntax subsystem. If an administrator triggers schema reload while concurrent LDAP query traffic is active, worker threads may access freed memory, resulting in use-after-free or double-free and a denial of service (server crash).

## Remediation

- workaround: Schedule schema reload operations during maintenance windows with reduced LDAP traffic. Minimize schema reload frequency; in replication topologies schema changes propagate automatically. Monitor for unexpected ns-slapd restarts during or immediately after schema reloads. Restrict write access to cn=schema,cn=config to dedicated administrative accounts via LDAP ACIs. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Directory Server 11 (redhat-ds:11/389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Directory Server 12 (redhat-ds:12/389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Directory Server 13 (389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (389-ds-base): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (389-ds-base): Version range not reported. Source: CNA: redhat

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:redhat:directory_server:11.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:directory_server:12.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:directory_server:13.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:389_directory_server:-:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 5 (medium); CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H; source: CNA: redhat

- CVSS 3.1: 5 (medium); CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H; source: NVD: nvd@nist.gov

- CVSS 3.1: 5 (medium); CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.35% as of 2026-11-06; percentile 28.74%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-416

## Exploit evidence

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

## References

- https://access.redhat.com/security/cve/CVE-2026-11791 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2485414 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-11791 (secalert@redhat.com; Mitigation, Vendor Advisory)

- https://bugzilla.redhat.com/show_bug.cgi?id=2485414 (secalert@redhat.com; Issue Tracking, Vendor Advisory)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-11791; retrieved 2026-11-07; source updated 2026-11-07

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-11791; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-11791; retrieved 2026-11-07; source updated Not reported

Revision: d7e0e597d38db46581c80a3ce88523e6b76f7ba381630d79c8dcb10177ca8dad

Canonical: https://y2.dev/cve/CVE-2026-11791

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