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VulnerabilityPublished Updated

CVE-2025-68795: Linux kernel · ethtool: Avoid overflowing userspace buffer on stats query

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f9dc0f45d2cd0189ce666288a29d2cc32c2e44d5 : patch Linux kernel soon.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% 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, 2026-06-16.

Patch
Available – fixed in f9dc0f45d2cd0189ce666288a29d2cc32c2e44d5, ca9983bc3a1189bd72f9ae449d925a66b2616326, 4066b5b546293f44cd6d0e84ece6e3ee7ff27093 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Jan 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
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < f9dc0f45d2cd0189ce666288a29d2cc32c2e44d5
Fixed in
  • f9dc0f45d2cd0189ce666288a29d2cc32c2e44d5
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ca9983bc3a1189bd72f9ae449d925a66b2616326
Fixed in
  • ca9983bc3a1189bd72f9ae449d925a66b2616326
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4066b5b546293f44cd6d0e84ece6e3ee7ff27093
Fixed in
  • 4066b5b546293f44cd6d0e84ece6e3ee7ff27093
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7bea09f60f2ad5d232e2db8f1c14e850fd3fd416
Fixed in
  • 7bea09f60f2ad5d232e2db8f1c14e850fd3fd416
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7b07be1ff1cb6c49869910518650e8d0abc7d25f
Fixed in
  • 7b07be1ff1cb6c49869910518650e8d0abc7d25f
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4afcb985355210e1688560dc47e64b94dad35d71
Fixed in
  • 4afcb985355210e1688560dc47e64b94dad35d71

Description

In the Linux kernel, the following vulnerability has been resolved: ethtool: Avoid overflowing userspace buffer on stats query The ethtool -S command operates across three ioctl calls: ETHTOOL_GSSET_INFO for the size, ETHTOOL_GSTRINGS for the names, and ETHTOOL_GSTATS for the values. If the number of stats changes between these calls (e.g., due to device reconfiguration), userspace's buffer allocation will be incorrect, potentially leading to buffer overflow. Drivers are generally expected to maintain stable stat counts, but some drivers (e.g., mlx5, bnx2x, bna, ksz884x) use dynamic counters, making this scenario possible. Some drivers try to handle this internally: - bnad_get_ethtool_stats() returns early in case stats.n_stats is not equal to the driver's stats count. - micrel/ksz884x also makes sure not to write anything beyond stats.n_stats and overflow the buffer. However, both use stats.n_stats which is already assigned with the value returned from get_sset_count(), hence won't solve the issue described here. Change ethtool_get_strings(), ethtool_get_stats(), ethtool_get_phy_stats() to not return anything in case of a mismatch between userspace's size and get_sset_size(), to prevent buffer overflow. The returned n_stats value will be equal to zero, to reflect that nothing has been returned. This could result in one of two cases when using upstream ethtool, depending on when the size change is detected: 1. When detected in ethtool_get_strings(): # ethtool -S eth2 no stats available 2. When detected in get stats, all stats will be reported as zero. Both cases are presumably transient, and a subsequent ethtool call should succeed. Other than the overflow avoidance, these two cases are very evident (no output/cleared stats), which is arguably better than presenting incorrect/shifted stats. I also considered returning an error instead of a "silent" response, but that seems more destructive towards userspace apps. Notes: - This patch does not claim to fix the inherent race, it only makes sure that we do not overflow the userspace buffer, and makes for a more predictable behavior. - RTNL lock is held during each ioctl, the race window exists between the separate ioctl calls when the lock is released. - Userspace ethtool always fills stats.n_stats, but it is likely that these stats ioctls are implemented in other userspace applications which might not fill it. The added code checks that it's not zero, to prevent any regressions.

References

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