Heap-based Buffer OverflowWeakness · CWE-122

CVE-2026-11610

HIGH · 8.8 CVSS v3.1 Published 2026-07-07

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

94/100

Remediation priority · Urgent

Remotely reachable Zero-click 7 weeks old

Official description

NVD · unedited

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 summary

dbcve analysis · high confidence

Heap buffer overflow in 389 Directory Server's SASL I/O layer where sasl_io_recv() copies an oversized LDAP UNBIND packet into a fixed 512-byte heap buffer without bounds checking, allowing up to ~2MB of attacker-controlled data to overflow and crash the server.

MitigationApply vendor patches for CVE-2026-11610 to 389-ds-base; ensure installations are updated to versions that include the sasl_io.c bounds-check fix.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: Low
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected?

dbcve checks

Work through these to decide whether this CVE applies to you.

Verify 389 Directory Server is installed

Run 'rpm -q 389-ds-base' or 'dnf list installed 389-ds-base' to confirm the package is present on the system

Affected if The package is not installed, so the vulnerability does not apply to this system
Determine installed version of 389-ds-base

Run 'rpm -q --qf "%{VERSION}-%{RELEASE}" 389-ds-base' or check the version through your package manager; compare this version against the fixed version provided in vendor security advisories for CVE-2026-11610

Affected if The installed version predates the patch for CVE-2026-11610 and no vendor update has been applied
Confirm SASL I/O layer is in use

Check the directory server configuration for SASL authentication settings: review 'cn=config' or 'cn=sasl,cn=config' in LDIF format, or inspect dse.ldif for 'sasl' or 'SASL' directives

Affected if SASL is enabled and configured, making the sasl_io_recv() code path active and reachable
Verify the sasl_io.c component is present

Check for the presence of the sasl_io.c source file in the installed paths (typically under /usr/include or within the source RPM), or confirm the binary linked libraries include the sasl I/O module

Affected if The server binary includes the sasl_io_recv() function, which is the vulnerable code path

A system is affected if 389-ds-base is installed with a version older than the patched release and SASL authentication is enabled, allowing the vulnerable sasl_io_recv() function to process oversized LDAP UNBIND packets.

Generated from the published advisory. Verify against your own configuration.

Remediation

From vendor data

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Apply vendor patches for CVE-2026-11610 to 389-ds-base; ensure installations are updated to versions that include the sasl_io.c bounds-check fix.

Have this fixed Scoped from the published advisory

Consultation3.0 h
Implementation6.0 h
Testing5.0 h
Review / QA3.0 h

17.0 hours of engineering $2,970

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Scan for this in your stack

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-11610 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2026-11610?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsA vendor remedy is published

Severity 8.8 High

Exploit likelihood EPSS, next 30 days 0.6%

Remediation

A high-priority fix

Have this fixed 17 hrs · Moderate

Typical engagement from $2,970

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2026-11610 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

Check your environment

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

CVSS breakdown

Am I affected?

Remediation

References