wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers (CVE-2026-64255) | HOL Guard CVE

High · CVSS 8.8CVE-2026-64255

wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers

Answer in brief

CVE-2026-64255 records a High severity (CVSS 8.8) vulnerability in wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers. 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 Jul 24, 2026Updated Aug 17, 2026Source checked Sep 20, 2026First seen by HOL Aug 5, 2026Material review Aug 17, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 8.8. 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.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=9aa3856d9b6f3f8bf085b5bbb5f3703578bf452b <1de92789ce31e46fa7e7d8e89c90b19cdb1c103b \|\| >=9aa3856d9b6f3f8bf085b5bbb5f3703578bf452b <fe7f339f63c9dc4ca546ed7ac38ba4bb3a99dcfc \|\| >=9aa3856d9b6f3f8bf085b5bbb5f3703578bf452b <f056fc2b927448d37eca6b6cacc3d1b0f67b20d2	1de92789ce31e46fa7e7d8e89c90b19cdb1c103b, fe7f339f63c9dc4ca546ed7ac38ba4bb3a99dcfc, f056fc2b927448d37eca6b6cacc3d1b0f67b20d2
Linux/Linuxgeneric	6.4	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 1de92789ce31e46fa7e7d8e89c90b19cdb1c103b if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers Three BA session handlers use ffs(ba_data->sta_mask) - 1 to derive a station ID without checking that sta_mask is non-zero. When sta_mask is zero, ffs() returns 0 and the subtraction wraps to 0xFFFFFFFF, causing an out-of-bounds access on fw_id_to_link_sta[]. Add WARN_ON_ONCE(!ba_data->sta_mask) guards before each ffs() call, consistent with the existing check in iwl_mld_ampdu_rx_start().

Quoted source text, attributed separately from HOL analysis.