LiveActive security incident?Get immediate response
CVE Record

CVE-2021-46949: sfc: farch: fix TX queue lookup in TX flush done handling

In the Linux kernel, the following vulnerability has been resolved: sfc: farch: fix TX queue lookup in TX flush done handling We're starting from a TXQ instance number ('qid'), not a TXQ type, so efx_get_tx_queue() is inappropriate (and could return NULL, leading to panics).

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-46949 is a Linux kernel bug in sfc farch transmit-queue handling. The source says incorrect queue lookup could return NULL and cause kernel panics. Business impact is mainly availability risk on affected Linux systems, but the provided data does not include CVSS, broad product detail, or exploitation evidence.

Executive priority

Treat this as a targeted Linux availability issue, not a confirmed widespread emergency. Prioritize internet-facing, high-availability, or network-intensive Linux systems if they match the affected kernels and driver path. Lack of severity scoring and exploit evidence lowers confidence, but kernel panic risk still warrants scheduled remediation.

Technical view

The resolved issue starts from a TX queue instance number, but used efx_get_tx_queue(), which expects a queue type. In the sfc farch TX flush completion path, that mismatch could produce a NULL queue reference and panic the kernel. Fixes are linked in Linux stable commits.

Likely exposure

Exposure appears limited to affected Linux kernel versions listed in the bundle, including 5.10, 5.10.36, 5.11.20, 5.12.3, and 5.13, where the sfc farch driver path is present and exercised. The bundle does not identify distributions, configurations, or hardware requirements.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation. The described failure mode is a kernel panic from NULL handling, suggesting denial-of-service potential rather than data theft. Trigger conditions are not fully described in the provided sources.

Researcher notes

Evidence is narrow: the CVE text describes the faulty lookup and panic risk, and references stable kernel commits. It does not provide CVSS, CWE, exploitability analysis, distribution advisories, or precise environmental prerequisites. Validation should rely on kernel provenance, backport status, and driver relevance.

Mitigation direction

  • Inventory Linux systems running the affected kernel versions listed in the bundle.
  • Check Linux stable or distribution vendor guidance for fixed kernel packages.
  • Prioritize hosts where the sfc farch driver path is present or in use.
  • Apply the appropriate kernel update through normal maintenance and reboot planning.
  • Monitor vendor advisories if distribution-specific backports obscure upstream version numbers.

Validation and detection

  • Confirm running kernel versions against the affected version list and vendor package metadata.
  • Check whether the sfc driver is present, loaded, or relevant on each host.
  • Verify the deployed kernel includes one of the referenced stable fixes or vendor backport.
  • Review system logs for unexplained kernel panics around network driver activity.
  • Document any systems deferred from patching and their compensating availability controls.
Prepared
Confidence
medium
Sources
6

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.

cve · low confidence lookup

CVE-2021-46949 mapping review

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

Open ATT&CK lookup
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
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical 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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux12804793b17c0e19115a90d98f2f3df0cb79e233, 12804793b17c0e19115a90d98f2f3df0cb79e233, 12804793b17c0e19115a90d98f2f3df0cb79e233, 12804793b17c0e19115a90d98f2f3df0cb79e233unaffected
LinuxLinux5.10, 0, 5.10.36, 5.11.20, 5.12.3, 5.13affected
Weakness

CWE details

No CWE listed

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