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CVE Record

CVE-2025-21712: md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime

In the Linux kernel, the following vulnerability has been resolved: md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct md_bitmap_stats"), following panic is reported: Oops: general protection fault, probably for non-canonical address RIP: 0010:bitmap_get_stats+0x2b/0xa0 Call Trace: <TASK> md_seq_show+0x2d2/0x5b0 seq_read_iter+0x2b9/0x470 seq_read+0x12f/0x180 proc_reg_read+0x57/0xb0 vfs_read+0xf6/0x380 ksys_read+0x6c/0xf0 do_syscall_64+0x82/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Root cause is that bitmap_get_stats() can be called at anytime if mddev is still there, even if bitmap is destroyed, or not fully initialized. Deferenceing bitmap in this case can crash the kernel. Meanwhile, the above commit start to deferencing bitmap->storage, make the problem easier to trigger. Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel race can access an MD software-RAID bitmap while it is being created or destroyed, causing a kernel crash. A successful trigger could disrupt affected servers or appliances. The supplied evidence does not demonstrate data theft, data modification, or remote exploitation, despite the CVSS impact ratings.

Executive priority

Treat this as a high-priority availability risk for Linux servers and appliances using MD RAID, especially multi-user or shared-compute systems. Patch through supported vendor channels during the next urgent maintenance window. Accelerate remediation where a kernel panic would interrupt critical operations or where untrusted local code can run.

Technical view

bitmap_get_stats() can dereference an uninitialized or destroyed MD bitmap, including its storage field, because its execution was not synchronized with bitmap lifetime changes. The kernel fix protects bitmap_get_stats() using bitmap_info.mutex. The reported failure is a general protection fault reached while reading MD status through procfs.

Likely exposure

Exposure is most likely on affected Linux systems using MD software RAID bitmap functionality, particularly where untrusted local users or processes can run. The supplied version data is ambiguous and should not be treated as a definitive fixed-version matrix. Internet exposure alone does not establish reachability.

Exploitation context

The CVSS vector describes a local, low-complexity attack requiring low privileges and no user interaction. The supplied sources report a reproducible kernel panic, but provide no evidence of exploitation in the wild. The CVE is not listed as CISA KEV in the bundle, and remote exploitation is not established.

Researcher notes

The evidence supports a lifetime-synchronization defect and kernel-panic outcome. The fix serializes bitmap_get_stats() with bitmap_info.mutex. Although CVSS assigns high confidentiality and integrity impacts, the supplied narrative demonstrates only a crash; stronger impact claims require additional evidence. Exact affected and fixed release boundaries remain unclear from the normalized version list.

Mitigation direction

  • Install a vendor-supported kernel containing the bitmap lifetime synchronization fix.
  • Check distribution or appliance advisories for the exact corrected package version.
  • Prioritize systems using MD software RAID and permitting untrusted local execution.
  • Apply normal change controls and reboot if required to activate the updated kernel.

Validation and detection

  • Inventory kernel versions and identify hosts using Linux MD software RAID.
  • Compare installed kernels with applicable Linux, Debian, or appliance vendor advisories.
  • Confirm the running kernel after remediation, not only the installed package.
  • Review kernel logs for general protection faults involving bitmap_get_stats or md_seq_show.
  • Assess local accounts, workloads, and services that permit untrusted code execution.
Prepared
Confidence
high
Sources
10

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

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CVE-2025-21712 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

1CVSS vectors
3Timeline events
2ADP providers
9Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-21712Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux32a7627cf3a35396a8e834faf34e38ae9f3b1309, 32a7627cf3a35396a8e834faf34e38ae9f3b1309, 32a7627cf3a35396a8e834faf34e38ae9f3b1309, 32a7627cf3a35396a8e834faf34e38ae9f3b1309, 32a7627cf3a35396a8e834faf34e38ae9f3b1309, 32a7627cf3a35396a8e834faf34e38ae9f3b1309unaffected
LinuxLinux2.6.13, 0, 5.15.209, 6.1.130, 6.6.80, 6.12.13, 6.13.2, 6.14affected
Weakness

CWE details

No CWE listed

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