Description

A flaw was found in Samba's CTDB, the clustered database service used by Samba. Insufficient integrity validation of received CTDB protocol packets allows malformed packets containing invalid field lengths, improperly terminated strings, or inconsistent packet sizes to be processed without adequate bounds checking. A remote attacker with access to the CTDB private network may trigger a denial of service through process crashes or excessive memory consumption and, in limited cases, disclose adjacent memory contents.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-08-14T15:17:09.870Z",
  "pubdate": "2026-08-14T15:17:09.870Z",
  "executiveSummary": "A vulnerability has been identified in Samba's CTDB, the clustered database service utilized by Samba deployments. The flaw stems from insufficient integrity validation of received CTDB protocol packets, resulting in inadequate bounds checking when processing malformed packets containing invalid field lengths, improperly terminated strings, or inconsistent packet sizes.\nThe primary impact of this vulnerability includes a denial of service through process crashes or excessive memory consumption, alongside limited leakage of adjacent memory contents. The affected system is Samba's CTDB service.\nExploitation requires a remote attacker to have network access to the CTDB private network. Successful exploitation allows the adversary to trigger resource exhaustion or memory disclosure conditions without necessarily requiring authentication, depending on the network segmentation and access controls enforced on the CTDB private interconnect.",
  "technicalDetails": "The root cause of the vulnerability lies within the input validation logic of Samba's CTDB protocol packet parser. When the CTDB service receives protocol packets across the network, the parsing routines fail to perform rigorous integrity checks and adequate bounds checking on critical header and payload fields. Specifically, the processing code consumes malformed packets that contain invalid field lengths, improperly terminated strings, or internal structural inconsistencies where the declared packet sizes do not match the actual data boundaries.\nThe vulnerable component is the CTDB protocol handling and packet processing subsystem within Samba's clustered database service. The attack flow begins when an attacker with network access to the CTDB private network constructs and transmits a specially crafted, malformed CTDB protocol packet to the targeted service. Because the application logic trusts or insufficiently validates the input parameters, it attempts to read or allocate memory based on untrusted size specifiers or unterminated string lengths.\nAs the malformed packet is processed, the lack of proper bounds checking leads to out-of-bounds memory reads or illegal memory access attempts. If the parsing routine reads past allocated buffer boundaries, it can inadvertently expose adjacent memory contents back to the requester or log outputs in limited scenarios. Alternatively, supplying excessively large field lengths or inconsistent structural sizes causes excessive memory consumption or triggers segmentation faults, resulting in abrupt process crashes and an effective denial of service for the clustering infrastructure.\nRegarding execution requirements, the attacker must have network connectivity to the CTDB private network interface, which is typically restricted to cluster nodes but could be exposed if network segmentation is misconfigured. Authentication requirements and specific privilege levels depend on the operational configuration of the CTDB interconnect, though internal protocol communication often operates with implicit trust between perceived cluster peers."
}