CVE-2026-15722: 389-ds-base: 389-ds-base: pre-authentication stack buffer overflow in get_ruvelement_from_berval() via unbounded replica id parsing
A flaw was found in 389 Directory Server (389-ds-base). The getruvelementfromberval() function in ldap/servers/plugins/replication/repl5ruv.c copies digit characters from a network-supplied RUV berval into a fixed 16-byte stack buffer (ridbuff[RIDSTRSIZE]) without bounds checking the loop counter. A remote unauthenticated attacker can crash the ns-slapd process by sending a crafted StartNSDS50ReplicationRequest LDAP extended operation (OID 2.16.840.1.113730.3.5.12) containing more than 16 consecutive digit characters in the replica ID field. The overflow occurs during payload decoding in decodestartreplextop(), before the replicaisupdatedn() authorization check runs, making it exploitable without credentials on default configurations where anonymous access is enabled. On production builds with stack protectors, the impact is limited to denial of service (process abort). The vulnerable code path is: decodestartreplextop() -> decoderuv() -> ruvinitfrombervals() -> getruvelementfromberval().
Other sources
A stack buffer overflow flaw was found in 389 Directory Server (389-ds-base). The getruvelementfromberval() function in repl5ruv.c copies digit characters from a network-supplied RUV berval into a fixed 16-byte stack buffer without bounds checking. A remote unauthenticated attacker can crash the LDAP server by sending a crafted StartNSDS50ReplicationRequest extended operation containing a replica ID field with more than 16 digit characters. The overflow occurs during payload decoding, before any authorization check. Stack protectors limit impact to denial of service.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Restrict/disable anonymous (unauthenticated) LDAP access so that exploitation of the StartNSDS50ReplicationRequest extended operation cannot be performed on default configurations where anonymous access is enabled.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-15722?
CVE-2026-15722 has a severity rating of 7.5, categorized as high.
What type of vulnerability is CVE-2026-15722?
CVE-2026-15722 is a stack buffer overflow vulnerability.
How can I fix CVE-2026-15722?
To mitigate CVE-2026-15722, upgrade to the latest version of 389-ds-base that contains the security patch.
What systems are affected by CVE-2026-15722?
CVE-2026-15722 affects the 389 Directory Server (389-ds-base) versions prior to the patched release.
What causes CVE-2026-15722?
CVE-2026-15722 is caused by unbounded parsing of a network-supplied RUV berval in the get_ruvelement_from_berval() function.