CVE-2026-78701
Description
A flaw was found in 389-ds-base. A remote, authenticated attacker could exploit a vulnerability in the Simple Authentication and Security Layer (SASL) UNBIND process. By sending a specially crafted request, the attacker can cause a connection to stall, leading to resource exhaustion and a Denial of Service (DoS) for the server.
Mitigation
To mitigate this issue, restrict network access to the 389-ds-base service to only trusted clients and networks. This can be achieved by configuring firewall rules to limit inbound connections to the LDAP ports (typically 389 for LDAP and 636 for LDAPS) to known, authorized IP addresses or subnets.
Example using `firewalld`:
bashReplace `<TRUSTED_IP_OR_SUBNET>` with the actual IP addresses or network ranges of your trusted clients. This action may impact legitimate clients if not configured correctly. A service restart is not required for firewall changes to take effect.
# firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<TRUSTED_IP_OR_SUBNET>" port port="389" protocol="tcp" accept'
# firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<TRUSTED_IP_OR_SUBNET>" port port="636" protocol="tcp" accept'
# firewall-cmd --reload
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Frequently Asked Questions
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