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PatchSiren cyber security CVE debrief

CVE-2026-11787 Red Hat CVE debrief

A flaw was found in 389 Directory Server. The ldap_utf8prev() function reads bytes before the start of a buffer without bounds checking, causing a heap buffer over-read in string filter parsing that may influence internal filter processing behavior.

Vendor
Red Hat
Product
Red Hat Directory Server 11
CVSS
MEDIUM 5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-30
Advisory published
2026-06-09
Advisory updated
2026-06-30

Who should care

Users of Red Hat Directory Server, 389 Directory Server, and Red Hat Enterprise Linux 7, 8, 9, and 10 are affected by this vulnerability.

Technical summary

The vulnerability is caused by a flaw in the ldap_utf8prev() function, which reads bytes before the start of a buffer without bounds checking. This can cause a heap buffer over-read in string filter parsing, potentially influencing internal filter processing behavior.

Defensive priority

MEDIUM

Recommended defensive actions

  • Apply patches or updates provided by Red Hat to address the vulnerability.
  • Refer to Red Hat's security advisory for CVE-2026-11787 for more information and mitigation steps: [ref-4].
  • Review and track the issue on Red Hat's bugzilla: [ref-5].

Evidence notes

The CVE-2026-11787 vulnerability was published on 2026-06-09T14:16:36.773Z and modified on 2026-06-12T18:38:54.423Z. The vulnerability has a CVSS score of 5 and is classified as MEDIUM severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-11787 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-11787

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-11787 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-11787

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.