Cve-2026-31613 — CraftedSignal Threat Feedhttps://feed.craftedsignal.io/tags/cve-2026-31613/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioMon, 22 Jan 2024 12:00:00 +0000CVE-2026-31613 SMB Client Out-of-Bounds Read Vulnerabilityhttps://feed.craftedsignal.io/briefs/2024-01-cve-2026-31613-smb-oob-read/Mon, 22 Jan 2024 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-cve-2026-31613-smb-oob-read/CVE-2026-31613 is an out-of-bounds read vulnerability in the SMB client when parsing symlink error responses, requiring patching to prevent potential information disclosure or denial-of-service.CVE-2026-31613 is a security vulnerability affecting the SMB (Server Message Block) client. The vulnerability stems from an out-of-bounds read error that occurs during the parsing of symlink error responses. This can potentially allow a malicious SMB server to send crafted responses that, when processed by the client, lead to reading memory outside of allocated buffers. While the specific details of exploitation are not provided in the source, the nature of an out-of-bounds read can lead to information disclosure or a denial-of-service condition. Microsoft has released a security update to address this vulnerability. Defenders should apply the patch to mitigate the risk.

Attack Chain

  1. A malicious SMB server is set up to serve crafted responses.
  2. A client attempts to connect to the malicious SMB server via the SMB protocol.
  3. The server sends a crafted SMB response containing a symlink error.
  4. The client attempts to parse the symlink error response.
  5. Due to the vulnerability, the client reads data beyond the allocated buffer.
  6. The out-of-bounds read could result in information disclosure, where sensitive data is exposed, or cause a denial-of-service.
  7. The attacker leverages the disclosed information for further exploitation (if information disclosure occurs).

Impact

Successful exploitation of CVE-2026-31613 could lead to information disclosure, potentially exposing sensitive data from the affected system’s memory. Alternatively, the vulnerability could be exploited to trigger a denial-of-service condition, disrupting the availability of the SMB client. The scope of impact depends on the specific data accessible via the out-of-bounds read and the system’s role within the network.

Recommendation

  • Apply the security update provided by Microsoft to patch CVE-2026-31613 on all systems using the SMB client to prevent potential out-of-bounds reads.
  • Enable SMB logging to monitor for unusual SMB responses or error conditions that may indicate exploitation attempts.
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