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Linux Kernel EUVDEUVD-2026-45802

| CVE-2026-64117 HIGH
Use After Free (CWE-416)
2026-07-19 Linux GHSA-8c2f-6crq-prr9
8.8
CVSS 3.1 · Vendor: Linux
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Join wireless range of mesh node
  2. Delivery
    Send unicast frame to unrouted mesh destination
  3. Exploit
    Trigger no-route kfree_skb in mesh forward
  4. Execution
    Freed skb->cb read by sta_stats_encode_rate
  5. Impact
    Kernel use-after-free (crash or info leak)

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the target to run the Linux mac80211 stack with 802.11s mesh networking enabled and actively forwarding unicast mesh traffic, plus the mac80211 fast-RX path in use - this is a non-default configuration limited to WiFi mesh deployments. The attacker must be within wireless/adjacent range (AV:A) and needs no authentication or credentials on the host (PR:N) and no user interaction (UI:N). The specific trigger is a forwarded unicast frame that hits the no-route branch of ieee80211_rx_mesh_data(), freeing the skb before the RX_QUEUED handler reads rate stats from it. Limiting factors: devices not running mesh mode, or drivers/paths where fast-RX is inactive, are not affected; requires radio proximity rather than remote Internet reachability.

Impact

Signals are mixed and lean toward moderate-to-low real-world priority despite the high CVSS. The provided CVSS is 8.8 (AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), implying adjacent, unauthenticated, low-complexity exploitation with full CIA impact. However, EPSS is only 0.16% (6th percentile), no KEV listing exists, and no POC is referenced - all consistent with a defensively-found upstream bug rather than in-the-wild exploitation. The high C/I/A rating (RCE-grade) appears optimistic for what the description shows: the vulnerable operation is a READ of freed/zeroed skb->cb by sta_stats_encode_rate, which most reliably yields a crash (DoS) or limited information disclosure (matching the 'Information Disclosure' tag) rather than confirmed code execution - verify impact scope with the vendor. A significant limiting factor the base score does not capture: the bug is only reachable when 802.11s mesh forwarding is configured and the fast-RX path is active, which is a non-default, niche deployment. Net: real but not urgent for most fleets; prioritize on devices actually running WiFi mesh.

Exploit ScenarioDerived

An attacker within wireless range of a Linux device operating as an 802.11s mesh node sends unicast frames addressed to a mesh destination for which the node has no route, driving the fast-RX forward path into the kfree_skb() no-route branch. The subsequent read of the freed skb->cb by sta_stats_encode_rate triggers the use-after-free, most likely crashing the kernel (DoS) or leaking freed slab contents. No public exploit code is currently identified, and the adjacent attack vector means the attacker must be on the same radio/mesh network.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 20, 2026

Memory corruption (slab use-after-free) in the Linux kernel's mac80211 wireless stack allows an adjacent attacker on an 802.11s mesh network to trigger a KASAN-detected use-after-free in the fast-RX receive path. When a unicast frame is forwarded by mesh_data and hits the no-route path, the shared skb->cb storage is freed (or zeroed) before the RX_QUEUED handler reads rate statistics from it via sta_stats_encode_rate, corrupting kernel memory. There is no public exploit identified at time of analysis and EPSS exploitation probability is low (0.16%, 6th percentile); the issue is a fixed upstream bug rather than an actively exploited one.

RemediationAI

Upstream fix available via stable-tree commits 2fb64f94f9afb774f2fa0c7835727d7a67f89f07 and d71c841be5d9e586ee7f36c0dc8ed4db0d9a1349 (https://git.kernel.org/stable/c/2fb64f94f9afb774f2fa0c7835727d7a67f89f07 and https://git.kernel.org/stable/c/d71c841be5d9e586ee7f36c0dc8ed4db0d9a1349); update to the patched stable release for your kernel series (the EUVD data cites the 7.0.x/7.1 and 6.4 branches - confirm the exact tagged version for your distribution before deploying). Apply the patch through your distribution's kernel update channel and reboot. If patching must be deferred, the most effective compensating control is to disable 802.11s mesh mode / mesh forwarding on affected wireless interfaces (e.g. tear down the mesh point interface), since the vulnerable code path is only exercised during unicast mesh forwarding - the trade-off is loss of mesh connectivity on that node. Where mesh is not needed at all, ensuring interfaces run only in station/AP mode avoids the path entirely.

Affected VersionsENISA

Linux patch: 7.0.11
Linux 3468e1e0c639032a603450f0830ccabfa76f5806 <2fb64f94f9afb774f2fa0c7835727d7a67f89f07
Linux patch: 7.1
Linux 3468e1e0c639032a603450f0830ccabfa76f5806 <d71c841be5d9e586ee7f36c0dc8ed4db0d9a1349
Linux patch: 0
Linux 6.4

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The flaw lives in Linux's mac80211 software MAC layer for SoftMAC WiFi drivers, specifically the receive fast-path (ieee80211_invoke_fast_rx) and mesh forwarding (ieee80211_rx_mesh_data). The root cause is a classic use-after-free / storage-aliasing bug (CWE-416, though the record lists CWE as N/A): the socket buffer control block (skb->cb) is aliased between IEEE80211_SKB_RXCB (RX status) and IEEE80211_SKB_CB (IEEE80211_TX_INFO). In the unicast mesh forward path, ieee80211_rx_mesh_data() memsets that TX_INFO to zero over the same buffer the caller still references as rx->skb, then either queues the skb for transmit (success) or kfree_skb()'s it (no-route) before returning RX_QUEUED. The caller's RX_QUEUED arm subsequently calls sta_stats_encode_rate(status) on memory that is either zeroed or already freed. The fix captures the encoded rate from status before invoking ieee80211_rx_mesh_data(), so the value is read while the memory is still valid. The CPE data identifies the affected product simply as cpe:2.3:a:linux:linux, i.e. the kernel itself.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Linux) PRIMARY 8.8 HIGH
AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 5.9 MEDIUM

Adjacent WiFi vector; AC:H because it requires non-default 802.11s mesh config and the no-route branch; freed-memory read gives limited info disclosure (C:L) and reliable crash (A:H), not confirmed RCE.

3.1 AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
4.0 AV:A/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE HIGH
Red Hat 7.0 MEDIUM

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

4
CVSS changed
Jul 20, 2026 - 15:22 NVD
8.8 (HIGH)
Patch available
Jul 19, 2026 - 17:03 EUVD
CVE Published
Jul 19, 2026 - 15:40 cve.org
UNKNOWN (no severity yet)
CVE Published
Jul 19, 2026 - 15:40 cve.org
HIGH 8.8

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: capture fast-RX rate before mesh reuses skb->cb

ieee80211_invoke_fast_rx() reads RX status through IEEE80211_SKB_RXCB(skb), which aliases the same skb->cb storage that ieee80211_rx_mesh_data() reuses as IEEE80211_TX_INFO. In the unicast forward path, mesh_data does:

info = IEEE80211_SKB_CB(fwd_skb); memset(info, 0, sizeof(*info));

on the same skb the caller still names via rx->skb, then either queues the skb for TX (success) or kfree_skb()'s it (no-route) before returning RX_QUEUED. The caller's RX_QUEUED arm then calls sta_stats_encode_rate(status) on memory that is either zeroed (success path) or freed (no-route path). The latter is KASAN slab-use-after-free in ieee80211_prepare_and_rx_handle.

Fix by encoding the rate from status before invoking ieee80211_rx_mesh_data(), so the RX_QUEUED arm consumes a value captured while status was still backed by valid memory.

Executive ViewAI

Why It Matters

CVE-2026-64117 is a HIGH-severity memory corruption vulnerability in the Linux kernel's wireless mesh networking stack (mac80211) that could enable denial of service or privilege escalation via adjacent network access. Organizations deploying 802.11s mesh networks should prioritize patching affected systems to prevent potential operational disruption and security compromise.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 94% exploitable
Prevalence
Ubiquitous
Linux kernel is ubiquitous, though the mac80211 mesh WiFi path is niche
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact
High

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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