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VulnerabilityPublished Updated

CVE-2026-68373: Linux kernel · wifi: at76c50x-usb: avoid length underflow in at76_guess_freq()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.1 High · fixed in fb1b50ab699211e777dca5ccfb648788b6a6e519 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 19% 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 cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in fb1b50ab699211e777dca5ccfb648788b6a6e519, f742d9c98b5c504fc9e6744eef13a721c2aea486, e165a1d295e7e814e13b0f92c86e5d48309509ce +5
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Aug 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 to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 1264b951463a00efebe1bb596499aaad620ec8af, < fb1b50ab699211e777dca5ccfb648788b6a6e519
Fixed in
  • fb1b50ab699211e777dca5ccfb648788b6a6e519
LinuxLinuxAffected
  • ≥ 1264b951463a00efebe1bb596499aaad620ec8af, < f742d9c98b5c504fc9e6744eef13a721c2aea486
Fixed in
  • f742d9c98b5c504fc9e6744eef13a721c2aea486
LinuxLinuxAffected
  • ≥ 1264b951463a00efebe1bb596499aaad620ec8af, < e165a1d295e7e814e13b0f92c86e5d48309509ce
Fixed in
  • e165a1d295e7e814e13b0f92c86e5d48309509ce
LinuxLinuxAffected
  • ≥ 1264b951463a00efebe1bb596499aaad620ec8af, < cb831aff2f850f72bc5ff5ad77d0a70bb5a84061
Fixed in
  • cb831aff2f850f72bc5ff5ad77d0a70bb5a84061
LinuxLinuxAffected
  • ≥ 1264b951463a00efebe1bb596499aaad620ec8af, < bcde7249d45f52f994a9872bedf45994472ade77
Fixed in
  • bcde7249d45f52f994a9872bedf45994472ade77
LinuxLinuxAffected
  • ≥ 1264b951463a00efebe1bb596499aaad620ec8af, < b406f33d234f98c8b310fdab5cbb492d85e98e49
Fixed in
  • b406f33d234f98c8b310fdab5cbb492d85e98e49

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() at76_guess_freq() checks only that the received frame is at least a bare 802.11 header (24 bytes) before subtracting the fixed management-body offset: len -= el_off; For both beacon and probe response frames, el_off is 36. If the frame is shorter than el_off, subtracting it causes the calculated IE length to wrap. The length is eventually passed to cfg80211_find_elem_match() as a very large unsigned value, so the element walk runs beyond the RX skb. This path is reached from at76_rx_tasklet() while scanning. If the device delivers a truncated beacon or probe response, the oversized IE length causes an out-of-bounds read during scanning. Skip the IE lookup if the frame does not reach the variable elements, before subtracting el_off.

References

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