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CVE Record

CVE-2025-38665: can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode

In the Linux kernel, the following vulnerability has been resolved: can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode Andrei Lalaev reported a NULL pointer deref when a CAN device is restarted from Bus Off and the driver does not implement the struct can_priv::do_set_mode callback. There are 2 code path that call struct can_priv::do_set_mode: - directly by a manual restart from the user space, via can_changelink() - delayed automatic restart after bus off (deactivated by default) To prevent the NULL pointer deference, refuse a manual restart or configure the automatic restart delay in can_changelink() and report the error via extack to user space. As an additional safety measure let can_restart() return an error if can_priv::do_set_mode is not set instead of dereferencing it unchecked.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2025-38665 is a Linux kernel CAN networking bug. A restart of a CAN device after Bus Off can hit a missing driver callback and dereference NULL. The bundle does not provide CVSS, severity, or confirmed business impact, so prioritize systems that actually use CAN interfaces.

Executive priority

Treat as targeted maintenance unless CAN-enabled Linux systems are business-critical. For automotive, industrial, lab, or embedded fleets using CAN, schedule expedited kernel updates because a kernel NULL dereference can affect availability.

Technical view

In can_changelink() and can_restart(), code could call can_priv::do_set_mode without confirming the driver implemented it. The kernel fix refuses manual restart or automatic restart delay configuration when the callback is absent, reports an extack error, and adds a defensive error return in can_restart().

Likely exposure

Exposure is most plausible on Linux systems using CAN networking with CAN drivers that do not implement do_set_mode. Risk is narrower for general servers without CAN interfaces. The source lists Linux as affected across multiple kernel version ranges, but distro-specific fixed package versions are incomplete here.

Exploitation context

The bundle reports no KEV listing and gives no evidence of active exploitation. Triggering requires interaction with CAN device restart paths, including manual restart from user space or delayed automatic restart after Bus Off, which is disabled by default according to the source.

Researcher notes

The public record is sparse: no CVSS, CWE, or exploitation evidence is provided. The affected-version data includes broad Linux ranges and commit references, so validation should focus on kernel patch ancestry, driver callback behavior, and CAN restart configuration.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Review Debian LTS or distribution advisories for fixed package availability.
  • Prioritize embedded, automotive, and industrial Linux systems using CAN.
  • Restrict who can configure CAN link restart behavior until patched.
  • Check vendor guidance if no fixed kernel package is available.

Validation and detection

  • Inventory Linux hosts with CAN interfaces or SocketCAN usage.
  • Identify running kernel versions and distribution patch status.
  • Check whether deployed CAN drivers implement do_set_mode.
  • Review CAN restart-delay configuration on exposed systems.
  • Confirm patched kernels include the referenced stable commits.
Prepared
Confidence
medium
Sources
8

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

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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
1ADP providers
7Source 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.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux39549eef3587f1c1e8c65c88a2400d10fd30ea17, 39549eef3587f1c1e8c65c88a2400d10fd30ea17, 39549eef3587f1c1e8c65c88a2400d10fd30ea17, 39549eef3587f1c1e8c65c88a2400d10fd30ea17, 39549eef3587f1c1e8c65c88a2400d10fd30ea17unaffected
LinuxLinux2.6.31, 0, 6.1.148, 6.6.101, 6.12.41, 6.15.9, 6.16affected
Weakness

CWE details

No CWE listed

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