CVE-2025-71150: ksmbd: Fix refcount leak when invalid session is found on session lookup
CSIRTS triage
- What
- ksmbd SMB server leaks a reference count when an invalid session is encountered during session lookup, causing resource exhaustion.
- Who is affected
- Systems running ksmbd SMB server with affected kernel versions.
- Urgency
- Medium priority; represents a denial-of-service vector through resource leakage but not currently exploited.
- Action
- Apply Linux kernel patch fixing the refcount leak in ksmbd session lookup.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-71150
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2025-711500.23% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 14% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2025-71150 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- high[UPDATE] [high] Linux Kernel: Multiple vulnerabilitiescert-bund
- unknownUbuntu Linux Kernel Multiple Vulnerabilitieshkcert
- unknownUSN-8620-4: Linux kernel (Intel IoTG) vulnerabilitiesubuntu
- unknownUSN-8620-3: Linux kernel (Intel IoTG) vulnerabilitiesubuntu
- unknownUSN-8620-2: Linux kernel (Azure FIPS) vulnerabilitiesubuntu
- highUSN-8620-1: Linux kernel vulnerabilitiesubuntu
- highUSN-8610-1: Linux kernel (Azure CVM) vulnerabilitiesubuntu
- highUSN-8575-3: Linux kernel vulnerabilitiesubuntu
- highUSN-8597-1: Linux kernel (IBM) vulnerabilitiesubuntu
- highUSN-8576-2: Linux kernel (NVIDIA Tegra) vulnerabilitiesubuntu
- highUSN-8575-2: Linux kernel vulnerabilitiesubuntu
- highUSN-8576-1: Linux kernel (NVIDIA Tegra) vulnerabilitiesubuntu
Recent advisories for ksmbd
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- mediumCVE-2025-21947: ksmbd: fix type confusion via race condition when using ipc_msg_send_requestmsrc · 2026-08-06
- highCVE-2026-64392: ksmbd: use opener credentials for delete-on-closemsrc · 2026-08-06
- highCVE-2026-64399: ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILEmsrc · 2026-08-06
- highCVE-2025-40039: ksmbd: Fix race condition in RPC handle list accessmsrc · 2026-08-06
- mediumCVE-2026-64397: ksmbd: serialize QUERY_DIRECTORY requests per filemsrc · 2026-08-06
- mediumCVE-2026-64578: ksmbd: validate compound request size before reading StructureSize2msrc · 2026-08-06
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