A flaw was found in 389-ds-base. (CVE-2026-78701)

This vulnerability (CVE-2026-78701) in 389-ds-base involves an out-of-bounds write triggered during the SASL UNBIND process. An authenticated remote attacker can exploit this by sending a specially crafted request that causes the LDAP server connection to stall, resulting in resource exhaustion and a denial of service. The issue is related to an incomplete fix for CVE-2026-11610 that may introduce connection stalls. The vulnerability impacts availability but does not affect confidentiality or integrity. Red Hat's advisory recommends restricting network access to LDAP ports (389 and 636) to trusted IP addresses or subnets as a mitigation. While a security update is available for Red Hat Enterprise Linux 9, the advisory does not explicitly confirm a patch for version 10. The CVSS vector is AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low complexity, low privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, and high availability impact.

The vulnerability allows a remote, authenticated attacker to cause a denial of service by stalling connections and exhausting server resources. There is no impact on confidentiality or integrity. The CVSS score of 6.5 reflects a medium severity primarily due to the high availability impact. No known exploits are reported in the wild.

Red Hat advises restricting network access to the 389-ds-base service to trusted clients only by configuring firewall rules to limit inbound connections to LDAP ports (389 and 636) to authorized IP addresses or subnets. This mitigation does not require a service restart. Customers should monitor Red Hat advisories for updates on patches for Red Hat Enterprise Linux 10. For Red Hat Enterprise Linux 9, a security update addressing this and related vulnerabilities is available and should be applied.