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CVE Record

CVE-2025-21873: scsi: ufs: core: bsg: Fix crash when arpmb command fails

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: bsg: Fix crash when arpmb command fails If the device doesn't support arpmb we'll crash due to copying user data in bsg_transport_sg_io_fn(). In the case where ufs_bsg_exec_advanced_rpmb_req() returns an error, do not set the job's reply_len. Memory crash backtrace: 3,1290,531166405,-;ufshcd 0000:00:12.5: ARPMB OP failed: error code -22 4,1308,531166555,-;Call Trace: 4,1309,531166559,-; <TASK> 4,1310,531166565,-; ? show_regs+0x6d/0x80 4,1311,531166575,-; ? die+0x37/0xa0 4,1312,531166583,-; ? do_trap+0xd4/0xf0 4,1313,531166593,-; ? do_error_trap+0x71/0xb0 4,1314,531166601,-; ? usercopy_abort+0x6c/0x80 4,1315,531166610,-; ? exc_invalid_op+0x52/0x80 4,1316,531166622,-; ? usercopy_abort+0x6c/0x80 4,1317,531166630,-; ? asm_exc_invalid_op+0x1b/0x20 4,1318,531166643,-; ? usercopy_abort+0x6c/0x80 4,1319,531166652,-; __check_heap_object+0xe3/0x120 4,1320,531166661,-; check_heap_object+0x185/0x1d0 4,1321,531166670,-; __check_object_size.part.0+0x72/0x150 4,1322,531166679,-; __check_object_size+0x23/0x30 4,1323,531166688,-; bsg_transport_sg_io_fn+0x314/0x3b0

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can trigger a kernel crash when a UFS ARPMB command fails, especially when the device does not support ARPMB. The documented impact is availability, not data theft or privilege escalation. The public bundle does not provide CVSS, CWE, or active exploitation evidence.

Executive priority

Treat this as a targeted availability risk for Linux systems with UFS storage, not a confirmed widespread compromise issue. Patch during the next kernel maintenance window, faster for devices where kernel crashes would disrupt production or field operations.

Technical view

In the UFS core BSG path, ufs_bsg_exec_advanced_rpmb_req() could return an error while the job reply_len was still set. bsg_transport_sg_io_fn() then copied user data and hit a hardened usercopy failure, causing a crash. Stable commits change error handling so reply_len is not set on failure.

Likely exposure

Exposure is most relevant to Linux systems using affected kernel versions with UFS storage and reachable UFS BSG functionality. The source data lists Linux kernel versions including 6.3, 6.6.81, 6.12.18, 6.13.6, and 6.14 as affected, but version range detail is incomplete.

Exploitation context

No source in the bundle reports active exploitation, and KEV is false. The public description shows a crash condition after an ARPMB operation fails. It does not state remote reachability, required privileges, or whether unprivileged users can trigger the affected path.

Researcher notes

The evidence supports a kernel crash in the UFS BSG ARPMB error path. The bundle does not include exploitability analysis, privilege requirements, CVSS, or CWE. Validation should focus on kernel provenance, UFS presence, and whether the referenced stable commits are included.

Mitigation direction

  • Apply the relevant Linux stable kernel fix from your vendor or upstream stable branch.
  • Prioritize systems with UFS storage and exposed BSG device access.
  • Check distribution kernel advisories for backported fixes matching the listed commits.
  • Restrict unnecessary local access to storage management interfaces where feasible.

Validation and detection

  • Inventory Linux kernel versions on systems with UFS storage.
  • Confirm whether the kernel includes one of the referenced stable fixes.
  • Review distribution advisories for CVE-2025-21873 backport status.
  • Check logs for UFS ARPMB failure messages and kernel crash traces.
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.

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CVE-2025-21873 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
0ADP providers
5Source 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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6ff265fc5ef660499e0edc4641647e99eed3f519, 6ff265fc5ef660499e0edc4641647e99eed3f519, 6ff265fc5ef660499e0edc4641647e99eed3f519, 6ff265fc5ef660499e0edc4641647e99eed3f519unaffected
LinuxLinux6.3, 0, 6.6.81, 6.12.18, 6.13.6, 6.14affected
Weakness

CWE details

No CWE listed

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