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CVE Record

CVE-2021-46965: mtd: physmap: physmap-bt1-rom: Fix unintentional stack access

In the Linux kernel, the following vulnerability has been resolved: mtd: physmap: physmap-bt1-rom: Fix unintentional stack access Cast &data to (char *) in order to avoid unintentionally accessing the stack. Notice that data is of type u32, so any increment to &data will be in the order of 4-byte chunks, and this piece of code is actually intended to be a byte offset. Addresses-Coverity-ID: 1497765 ("Out-of-bounds access")

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-46965 is a Linux kernel bug in an MTD physmap ROM driver. The code could accidentally read past a small stack variable because pointer arithmetic used 32-bit units instead of bytes. Business urgency is unclear because no CVSS score, CWE, or exploitation evidence is provided.

Executive priority

Track and remediate through normal kernel patch management unless local exposure confirms the affected driver is used in sensitive systems. Escalation above routine priority is not supported by the provided evidence.

Technical view

The vulnerable logic is in mtd: physmap: physmap-bt1-rom. A u32 variable address was incremented as u32-sized chunks where byte offsets were intended, causing unintentional stack access. The resolved fix casts &data to char * to make byte-wise addressing explicit. Coverity flagged it as out-of-bounds access.

Likely exposure

Exposure appears limited to Linux systems using affected kernel builds with the physmap-bt1-rom MTD driver path present or enabled. The source lists Linux kernel 5.10-era affected versions and stable commit fixes, but does not describe distributions, configurations, or reachable attack surfaces.

Exploitation context

No active exploitation is cited, and the CVE is not marked KEV. The provided sources do not describe a public exploit, attack prerequisites, privilege requirements, or whether the bug is reachable from untrusted input.

Researcher notes

The key issue is incorrect pointer arithmetic on a u32 stack object, addressed by changing the pointer type before applying byte offsets. Source data lacks CVSS, CWE, exploitability analysis, and distribution mapping, so validation should focus on code presence and vendor backport status.

Mitigation direction

  • Check vendor kernel advisories for backported fixes covering CVE-2021-46965.
  • Upgrade to a kernel containing one of the referenced stable commits.
  • Prioritize systems using MTD physmap ROM support or board-specific bt1 ROM code.
  • If upgrades are delayed, review whether the affected driver is built or loaded.

Validation and detection

  • Inventory deployed Linux kernel versions and vendor patch levels.
  • Confirm whether physmap-bt1-rom code is present in each kernel build.
  • Verify the fix uses byte-wise access by casting &data to char *.
  • Record whether any affected systems expose relevant MTD functionality.
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

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CVE-2021-46965 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
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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb3e79e7682e075326df8041b826b03453acacd0a, b3e79e7682e075326df8041b826b03453acacd0a, b3e79e7682e075326df8041b826b03453acacd0a, b3e79e7682e075326df8041b826b03453acacd0aunaffected
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.