What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-24 · updated 2026-10-19
• Weakness: CWE-125

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().

Affected products

• Linux kernel: from 6.4 before 6.18.38; from 6.19 before 7.1.3 — fixed in 6.18.38, 7.1.3

How to fix

Upgrade to a fixed version: Linux kernel 6.18.38, 7.1.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1de92789ce31e46fa7e7d8e89c90b19cdb1c103b
• https://git.kernel.org/stable/c/f056fc2b927448d37eca6b6cacc3d1b0f67b20d2
• https://git.kernel.org/stable/c/fe7f339f63c9dc4ca546ed7ac38ba4bb3a99dcfc

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