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CVE Record

CVE-2021-46960: cifs: Return correct error code from smb2_get_enc_key

In the Linux kernel, the following vulnerability has been resolved: cifs: Return correct error code from smb2_get_enc_key Avoid a warning if the error percolates back up: [440700.376476] CIFS VFS: \\otters.example.com crypt_message: Could not get encryption key [440700.386947] ------------[ cut here ]------------ [440700.386948] err = 1 [440700.386977] WARNING: CPU: 11 PID: 2733 at /build/linux-hwe-5.4-p6lk6L/linux-hwe-5.4-5.4.0/lib/errseq.c:74 errseq_set+0x5c/0x70 ... [440700.397304] CPU: 11 PID: 2733 Comm: tar Tainted: G OE 5.4.0-70-generic #78~18.04.1-Ubuntu ... [440700.397334] Call Trace: [440700.397346] __filemap_set_wb_err+0x1a/0x70 [440700.397419] cifs_writepages+0x9c7/0xb30 [cifs] [440700.397426] do_writepages+0x4b/0xe0 [440700.397444] __filemap_fdatawrite_range+0xcb/0x100 [440700.397455] filemap_write_and_wait+0x42/0xa0 [440700.397486] cifs_setattr+0x68b/0xf30 [cifs] [440700.397493] notify_change+0x358/0x4a0 [440700.397500] utimes_common+0xe9/0x1c0 [440700.397510] do_utimes+0xc5/0x150 [440700.397520] __x64_sys_utimensat+0x88/0xd0

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects CIFS/SMB file sharing code. When an encryption key lookup fails, the kernel can return the wrong error value and produce a warning during file operations. The public sources do not show data theft, privilege escalation, or active exploitation.

Executive priority

Treat this as a targeted Linux file-service reliability issue unless vendor guidance adds higher impact. Patch through normal kernel maintenance, with faster handling for production systems depending on encrypted SMB mounts.

Technical view

The flaw is in cifs smb2_get_enc_key error handling. A non-standard error return can propagate into CIFS writeback and setattr paths, causing errseq_set warnings when encrypted SMB operations fail. Kernel stable commits are referenced as fixes, but the bundle provides no CVSS, CWE, or exploit detail.

Likely exposure

Exposure is most likely on Linux systems running affected kernel versions that mount CIFS/SMB shares, especially where SMB encryption is used. Systems not using CIFS mounts are unlikely to encounter the affected code path.

Exploitation context

CISA KEV status is false in the bundle. The provided sources do not report active exploitation. The described trigger is an operational error path in CIFS encryption handling, not a documented remote attack chain.

Researcher notes

The evidence is limited: no CVSS, CWE, CPEs, or exploit narrative are provided. Affected-version data mixes upstream ranges and commit references, so distro-specific validation must rely on vendor backports and kernel changelogs.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable CIFS fixes.
  • Prioritize Linux systems using CIFS/SMB mounts with encryption enabled.
  • Check distribution advisories for backported fixes before judging by version alone.
  • Monitor kernel logs for CIFS encryption key and errseq warnings.

Validation and detection

  • Inventory Linux hosts using CIFS or SMB mounts.
  • Confirm the running kernel includes the relevant stable fix or vendor backport.
  • Review kernel logs for CIFS VFS encryption key errors.
  • Validate CIFS file operations after updating affected hosts.
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

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CVE-2021-46960 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
2ADP providers
8Source 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
LinuxLinux61cfac6f267dabcf2740a7ec8a0295833b28b5f5, 61cfac6f267dabcf2740a7ec8a0295833b28b5f5, 61cfac6f267dabcf2740a7ec8a0295833b28b5f5, 61cfac6f267dabcf2740a7ec8a0295833b28b5f5, 61cfac6f267dabcf2740a7ec8a0295833b28b5f5, 61cfac6f267dabcf2740a7ec8a0295833b28b5f5, 61cfac6f267dabcf2740a7ec8a0295833b28b5f5unaffected
LinuxLinux4.11, 0, 4.14.233, 4.19.191, 5.4.118, 5.10.36, 5.11.20, 5.12.3, 5.13affected
Weakness

CWE details

No CWE listed

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