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CVE Record

CVE-2025-22074: ksmbd: fix r_count dec/increment mismatch

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix r_count dec/increment mismatch r_count is only increased when there is an oplock break wait, so r_count inc/decrement are not paired. This can cause r_count to become negative, which can lead to a problem where the ksmbd thread does not terminate.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2025-22074 is a Linux kernel ksmbd defect where internal reference counting can become negative. The stated consequence is that a ksmbd thread may not terminate. This points to an availability and operational stability risk on systems using kernel SMB services, not a confirmed data theft or code execution issue.

Executive priority

Handle this as a targeted kernel maintenance item for SMB-serving Linux hosts. It does not currently justify emergency treatment from the provided evidence, but exposed file-service infrastructure should be patched during the next appropriate maintenance window after vendor packages are available.

Technical view

The resolved kernel issue is an r_count increment/decrement mismatch in ksmbd. r_count is incremented only during oplock break waits, so later decrement paths can be unpaired and drive the counter negative. Sources state this can prevent ksmbd thread termination. No CVSS, CWE, exploit method, or confirmed exploitation is provided.

Likely exposure

Exposure is most relevant to Linux systems using ksmbd, the in-kernel SMB server. The bundle lists Linux kernel versions and stable commits, but does not provide CPEs or a complete deployment inventory signal. Systems not running ksmbd are less likely to be exposed to this specific defect.

Exploitation context

The source bundle does not report active exploitation, and KEV is false. It also does not describe attacker prerequisites, remote reachability, or a proof of concept. Treat exploitation details as unconfirmed and focus validation on whether ksmbd is enabled and whether fixed kernel builds are installed.

Researcher notes

The key evidence is the upstream description: unpaired r_count operations around oplock break wait handling may make the counter negative and block ksmbd thread termination. The bundle lacks CVSS, CWE mapping, exploitability analysis, and complete version-range semantics, so conclusions should stay conservative.

Mitigation direction

  • Check Linux distribution advisories for kernel packages containing the referenced stable fixes.
  • Prioritize updates on systems that expose ksmbd-based SMB services.
  • Disable ksmbd where kernel SMB service is not required.
  • Track vendor guidance because the bundle does not name workaround settings.

Validation and detection

  • Inventory systems running Linux kernels with ksmbd available or enabled.
  • Confirm installed kernel versions against distribution advisories and referenced stable commits.
  • Review service configuration to distinguish ksmbd from user-space Samba deployments.
  • Monitor affected hosts for lingering ksmbd threads or SMB service instability.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2025-22074 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux09aeab68033161cb54f194da93e51a11aee6144b, a4261bbc33fbf99b99c80aa3a2c5097611802980, f17d1c63a76b0fe8e9c78023a86507a3a6d62cfa, 3aa660c059240e0c795217182cf7df32909dd917, 3aa660c059240e0c795217182cf7df32909dd917, 6.6.84, 6.12.20, 6.13.8unaffected
LinuxLinux6.14, 0, 6.6.87, 6.12.23, 6.13.11, 6.14.2, 6.15affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.