CVE-2025-40170: Linux kernel · net: use dst_dev_rcu() in sk_setup_caps()
Source GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in a805729c0091073d8f0415cfa96c7acd1bc17a48 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in a805729c0091073d8f0415cfa96c7acd1bc17a48, 99a2ace61b211b0be861b07fbaa062fca4b58879, 9f22b5f7f1a32f8bbcc82bf34e34ea63523fcd02 +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 a805729c0091073d8f0415cfa96c7acd1bc17a48, 99a2ace61b211b0be861b07fbaa062fca4b58879, 9f22b5f7f1a32f8bbcc82bf34e34ea63523fcd02 or 5d1be493d1110c9e720b4c51a6e587bb2fb4ac12.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix has been implemented in the Linux kernel to use RCU protection for accesses to dst->dev in the affected functions. Users should update to a Linux kernel version that includes this patch. Since no specific patched versions are provided, check the vendor or kernel mailing list advisories for the exact fixed versions and apply updates accordingly.
Description
A high-severity vulnerability in the Linux kernel related to improper use of RCU (Read-Copy-Update) mechanisms in network code has been resolved. The issue involved unsafe access to the destination device pointer (dst->dev) in several kernel functions, including sk_setup_caps(), sk_dst_gso_max_size(), ip6_dst_mtu_maybe_forward(), ip_dst_mtu_maybe_forward(), and ip4_dst_hoplimit(). The fix applies RCU protection to these accesses to prevent potential memory safety issues.
References
- nvd.nist.gov/vuln/detail/CVE-2025-40170 (opens in a new tab)
- git.kernel.org/stable/c/5d1be493d1110c9e720b4c51a6e587bb2fb4ac12 (opens in a new tab)
- git.kernel.org/stable/c/99a2ace61b211b0be861b07fbaa062fca4b58879 (opens in a new tab)
- git.kernel.org/stable/c/a805729c0091073d8f0415cfa96c7acd1bc17a48 (opens in a new tab)