md/md-llbitmap: prevent create failure bitmap UAF (CVE-2026-90277) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-90277

md/md-llbitmap: prevent create failure bitmap UAF

Answer in brief

CVE-2026-90277 records a Unknown severity vulnerability in md/md-llbitmap: prevent create failure bitmap UAF. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 17, 2026Updated Sep 17, 2026Source checked Sep 17, 2026First seen by HOL Sep 17, 2026Material review Sep 17, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=5ab829f1971dc99f2aac10846c378e67fc875abc <930cc4f1af5a1afcd545a6ba00e38921ff8401e0 \|\| >=5ab829f1971dc99f2aac10846c378e67fc875abc <2f0722435ce3a844dbb66b9bb0a18229dcc8739c \|\| >=5ab829f1971dc99f2aac10846c378e67fc875abc <2116c2f0a0e547615886900e2ed8c529c016499b	930cc4f1af5a1afcd545a6ba00e38921ff8401e0, 2f0722435ce3a844dbb66b9bb0a18229dcc8739c, 2116c2f0a0e547615886900e2ed8c529c016499b
Linux/Linuxgeneric	6.18	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 930cc4f1af5a1afcd545a6ba00e38921ff8401e0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 17, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: md/md-llbitmap: prevent create failure bitmap UAF llbitmap_create() publishes mddev->bitmap before reading the bitmap superblock. This is needed because llbitmap_read_sb() can initialize a new bitmap and flush it through helpers that use mddev->bitmap. If llbitmap_read_sb() fails, the old cleanup dropped bitmap_info.mutex and freed llbitmap before clearing mddev->bitmap. Readers such as /proc/mdstat rely on bitmap_info.mutex to keep the bitmap pointer stable while collecting bitmap stats, so they could observe the stale pointer after the failed create path released the mutex. Clear mddev->bitmap while still holding bitmap_info.mutex, then free the failed llbitmap after dropping the mutex. This makes mutex-protected readers see either a live bitmap or no bitmap.

Quoted source text, attributed separately from HOL analysis.