CVE-2023-34966
Published: 20 July 2023
Summary
CVE-2023-34966 is a high-severity Infinite Loop (CWE-835) vulnerability in Samba Samba. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 5.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2023-34966 is an infinite loop vulnerability in Samba's mdssvc RPC service used for Spotlight indexing. The flaw resides in the core unmarshalling function sl_unpack_loop(), which fails to validate a client-supplied count field for an array-like structure in incoming Spotlight mdssvc RPC packets; supplying a value of zero causes the function to loop indefinitely and consume 100% CPU. The affected component is the Samba server implementation of the mdssvc protocol.
An unauthenticated remote attacker can exploit the issue by sending a single malformed RPC request over the network. Because the CVSS vector indicates no privileges or user interaction are required, the attack results in a denial-of-service condition that renders the Samba service unresponsive while the CPU remains saturated.
Red Hat has published multiple errata (RHSA-2023:6667, RHSA-2023:7139, RHSA-2024:0423, RHSA-2024:0580, and RHSA-2024:4101) that deliver patched Samba packages addressing the vulnerability.
The EPSS score has remained in the 0.14–0.16 range since disclosure, indicating moderate but not sharply increasing exploitation interest.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-39005
Vulnerability details
An infinite loop vulnerability was found in Samba's mdssvc RPC service for Spotlight. When parsing Spotlight mdssvc RPC packets sent by the client, the core unmarshalling function sl_unpack_loop() did not validate a field in the network packet that contains the…
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count of elements in an array-like structure. By passing 0 as the count value, the attacked function will run in an endless loop consuming 100% CPU. This flaw allows an attacker to issue a malformed RPC request, triggering an infinite loop, resulting in a denial of service condition.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.