How severe is CVE-2026-74409?

CVE-2026-74409 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-74409?

CVE-2026-74409 affects the following packages: Kernel (Linux). Ecosystems affected: Linux.

How do I fix CVE-2026-74409?

Update Kernel to 6.18.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-74409 is resolved across your whole dependency graph.

How do I detect CVE-2026-74409 in my Linux dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-74409 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-74409?

O3 pinpoints whether CVE-2026-74409 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-74409 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-74409 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-74409 published, and has it been updated?

CVE-2026-74409 was published on August 15, 2026 and was last updated on August 18, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐧

🐧 Linux

Not in CISA KEV

HIGH severity

CVE-2026-74409

HIGH

CVE-2026-74409 is a high-severity (CVSS 8.8) vulnerability in Kernel. O3 Security confirms whether CVE-2026-74409 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

wifi: rtw89: add bounds check on firmware mac_id in link lookup

Published

Aug 15, 2026

Updated

Aug 18, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐧Kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.

Description

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

wifi: rtw89: add bounds check on firmware mac_id in link lookup

The mac_id field in RX descriptors is 8 bits wide (0-255), but assoc_link_on_macid[] has only RTW89_MAX_MAC_ID_NUM (128) entries. While the driver currently assigns mac_id values below 128, the descriptor value comes from firmware and is not validated before use as an array index. Add a defensive bounds check in rtw89_assoc_link_rcu_dereference() to guard against out-of-range firmware values.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐧Linux	`Kernel`	≥ 6.14.0&&< 6.18.40	6.18.40

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Kernel to 6.18.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-74409 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-74409 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-74409. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw89: add bounds check on firmware mac_id in link lookup The mac_id field in RX descriptors is 8 bits wide (0-255), but assoc_link_on_macid[] has only RTW89_MAX_MAC_ID_NUM (128) entries. While the driver currently assigns mac_id values below 128, the descriptor value comes from firmware and is not validated before use as an array index. Add a defensive bounds check in rtw89_assoc_link_rcu_dereference() to guard against out-of-range firmware values.

O3 Security · Impact-Aware SCA

Is CVE-2026-74409 in your dependencies?

O3 detects CVE-2026-74409 across Linux dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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