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CVE Record

CVE-2025-40170: net: use dst_dev_rcu() in sk_setup_caps()

In the Linux kernel, the following vulnerability has been resolved: net: use dst_dev_rcu() in sk_setup_caps() Use RCU to protect accesses to dst->dev from sk_setup_caps() and sk_dst_gso_max_size(). Also use dst_dev_rcu() in ip6_dst_mtu_maybe_forward(), and ip_dst_mtu_maybe_forward(). ip4_dst_hoplimit() can use dst_dev_net_rcu().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel networking bug where code could read a network destination device pointer without expected RCU protection during concurrent kernel updates. The public record does not provide CVSS, impact type, crash evidence, or exploit evidence. Treat it as a kernel maintenance risk until vendor advisories clarify severity.

Executive priority

Medium operational attention, not emergency by current evidence. Schedule kernel updates through normal vulnerability management, and escalate if your vendor rates it high or confirms exploitable impact.

Technical view

The fix changes networking paths including sk_setup_caps(), sk_dst_gso_max_size(), IPv4/IPv6 MTU forwarding helpers, and hoplimit handling to access dst->dev or its network namespace through RCU-safe helpers. Sources identify Linux kernel versions and stable commits, but do not describe attacker control, privilege requirements, or consequences.

Likely exposure

Exposure is limited to systems running affected Linux kernel builds or vendor kernels that include the vulnerable code and lack the referenced stable fixes. The bundle lists Linux as the affected product, but does not map distribution package versions.

Exploitation context

The CVE is not marked KEV, and the provided sources do not claim active exploitation, public exploit availability, or a proven attack path. Any exploitation assumptions would be unsupported from this bundle.

Researcher notes

The strongest evidence is the upstream fix description, which indicates an RCU lifetime or concurrency issue around dst device access. The bundle lacks crash traces, CWE mapping, CVSS, exploitability analysis, and distro-specific affected ranges.

Mitigation direction

  • Apply Linux kernel or distribution updates containing the referenced stable fixes.
  • Check vendor advisories for patched package versions and reboot requirements.
  • Prioritize production, internet-facing, and multi-tenant Linux hosts for kernel updates.
  • If patching is delayed, monitor vendor guidance for any named workaround.

Validation and detection

  • Inventory running kernel versions across Linux assets.
  • Compare deployed kernels with distribution advisories for CVE-2025-40170.
  • Confirm whether kernel source or changelog includes the referenced stable commits.
  • Track CVE updates for CVSS, impact details, or exploitation evidence.
Prepared
Confidence
medium
Sources
5

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

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CVE-2025-40170 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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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
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

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

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36unaffected
LinuxLinux4.13, 0, 6.12.64, 6.17.3, 6.18affected
Weakness

CWE details

No CWE listed

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