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VulnerabilityPublished Updated

CVE-2026-64037: Linux kernel · Improper Input Validation

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in cbe1c8245e4469d1aa6e12e5d913611376d23788 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in cbe1c8245e4469d1aa6e12e5d913611376d23788, 92cee08dc4f00e77fd1317e4343c5d458b0abab7, 9e360e610a73f62432e986775023d5382773f045
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade Linux kernel to cbe1c8245e4469d1aa6e12e5d913611376d23788, 92cee08dc4f00e77fd1317e4343c5d458b0abab7 or 9e360e610a73f62432e986775023d5382773f045.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ d1e879ec600f9b3bdd253167533959facfefb17b, < cbe1c8245e4469d1aa6e12e5d913611376d23788
Fixed in
  • cbe1c8245e4469d1aa6e12e5d913611376d23788
LinuxLinuxAffected
  • ≥ d1e879ec600f9b3bdd253167533959facfefb17b, < 92cee08dc4f00e77fd1317e4343c5d458b0abab7
Fixed in
  • 92cee08dc4f00e77fd1317e4343c5d458b0abab7
LinuxLinuxAffected
  • ≥ d1e879ec600f9b3bdd253167533959facfefb17b, < 9e360e610a73f62432e986775023d5382773f045
Fixed in
  • 9e360e610a73f62432e986775023d5382773f045
LinuxLinuxAffected
  • =6.15
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled When the TLC notification disables AMSDU for a TID, the MLD driver sets max_tid_amsdu_len to the sentinel value 1. The TSO segmentation path in iwl_mld_tx_tso_segment() checks for zero but not for this sentinel, allowing it to reach the num_subframes calculation: num_subframes = (max_tid_amsdu_len + pad) / (subf_len + pad) = (1 + 2) / (1534 + 2) = 0 This zero propagates to iwl_tx_tso_segment() which sets: gso_size = num_subframes * mss = 0 Calling skb_gso_segment() with gso_size=0 creates over 32000 tiny segments from a single GSO skb. This floods the TX ring with ~1024 micro-frames (the rest are purged), creating a massive burst of TX completion events that can lead to memory corruption and a subsequent use-after-free in TCP's retransmit queue (refcount underflow in tcp_shifted_skb, NULL deref in tcp_rack_detect_loss). The MVM driver is immune because it checks mvmsta->amsdu_enabled before reaching the num_subframes calculation. The MLD driver has no equivalent bitmap check and relies solely on max_tid_amsdu_len, which does not catch the sentinel value. Fix this by detecting the sentinel value (max_tid_amsdu_len == 1) at the existing check and falling back to non-AMSDU TSO segmentation. Also add a WARN_ON_ONCE guard after the num_subframes division as defense-in-depth to catch any future code paths that produce zero through a different mechanism.

References

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