CVE-2026-103547: Null Pointer Dereference

Q: Which systems are exposed to remote authentication impersonation?

Systems running ldapd on OpenBSD 7.8 without errata 057 or OpenBSD 7.9 without errata 021 are exposed if ldapd is reachable by a remote attacker. ldapd is not enabled by default.

Q: What does an attacker need to exploit the authentication issue?

The attacker needs network reachability to ldapd. No prior privileges or user interaction are required, but exploitation has high attack complexity because a closed connection must be followed by another connection that reuses both the LDAP child process client file descriptor and LDAP message ID.

Q: What is the impact of successful exploitation?

An attacker can complete an LDAP Bind as another identity by receiving an earlier delegated BSD authentication result. A missing connection can also trigger a NULL pointer dereference.

Q: How can this be remediated?

Apply errata 057 for OpenBSD 7.8 or errata 021 for OpenBSD 7.9. If patching cannot occur immediately, disable ldapd or restrict network access to it so remote attackers cannot reach the service.

Published Sep 30, 2026

Updated

In ldapd in OpenBSD 7.8 before errata 057 and 7.9 before errata 021, delegated BSD authentication results are correlated only by the LDAP child process client file descriptor and LDAP message ID. After a connection closes, a later connection that reuses the same file descriptor and message ID can receive the earlier authentication result. A remote attacker who can reach ldapd can complete a Bind as another identity. A missing connection can also cause a NULL pointer dereference. (ldapd is not enabled by default.)

Affected Software

1 affected component

OpenBSD ldapd<7.8 errata 057, <7.9 errata 021

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade OpenBSD ldapd to a version that resolves this vulnerability.
Patch errata 057
Upgrade
Upgrade OpenBSD ldapd to a version that resolves this vulnerability.
Patch errata 021

Event History

Sep 30, 2026

CVE Published

via MITRE·07:40 PM

Data Sourced

via MITRE·07:40 PM

DescriptionWeakness

Data Sourced

via NVD·08:17 PM

DescriptionSeverityWeakness

Frequently Asked Questions

Which systems are exposed to remote authentication impersonation?

Systems running ldapd on OpenBSD 7.8 without errata 057 or OpenBSD 7.9 without errata 021 are exposed if ldapd is reachable by a remote attacker. ldapd is not enabled by default.

What does an attacker need to exploit the authentication issue?

The attacker needs network reachability to ldapd. No prior privileges or user interaction are required, but exploitation has high attack complexity because a closed connection must be followed by another connection that reuses both the LDAP child process client file descriptor and LDAP message ID.

What is the impact of successful exploitation?

An attacker can complete an LDAP Bind as another identity by receiving an earlier delegated BSD authentication result. A missing connection can also trigger a NULL pointer dereference.

How can this be remediated?

Apply errata 057 for OpenBSD 7.8 or errata 021 for OpenBSD 7.9. If patching cannot occur immediately, disable ldapd or restrict network access to it so remote attackers cannot reach the service.

CVE-2026-103547: Null Pointer Dereference

Affected Software

Remediation

Event History

Frequently Asked Questions

Which systems are exposed to remote authentication impersonation?

What does an attacker need to exploit the authentication issue?

What is the impact of successful exploitation?

How can this be remediated?

Company

Resources

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Frequently Asked Questions

Which systems are exposed to remote authentication impersonation?

What does an attacker need to exploit the authentication issue?

What is the impact of successful exploitation?

How can this be remediated?