netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()
CVE-2026-74695 · published 22 Aug 2026
How serious is it
- Severity: high, CVSS score 7.5 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-74695?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 to < 4db3b48a966ed479b99cc8319ea9e46d4f7c703b, 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 to < 274f544a32c08638ee887f2e27e3235b6b1237d4, 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 to < 12afa450a6a6c0cce2c42b7545a9958f62d8a00c, 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 to < 538e67e8c7889cf5f93951f5309d1bcb41f86036
- Linux Linux: 4.18
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()
Incoming skbs passing through netfilter flowtable offload hooks (or XFRM
offload path) might already carry a ref-counted dst_entry assigned during
earlier RX or routing steps.
Calling skb_dst_set_noref() when skb already holds a ref-counted dst
overwrites skb->_skb_refdst, leaking the previous dst_entry reference
count and triggering a DEBUG_NET_WARN_ON_ONCE assertion in
skb_dst_check_unset():
WARNING: at skb_dst_check_unset include/linux/skbuff.h:1170
WARNING: at skb_dst_set_noref include/linux/skbuff.h:1234
WARNING: at nf_flow_offload_ip_hook+0xf6c/0x2b60 net/netfilter/nf_flow_table_ip.c:864
Drop any existing dst_entry reference with skb_dst_drop(skb) before
setting the non-referenced flowtable destination.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/4db3b48a966ed479b99cc8319ea9e46d4f7c703b
- git.kernel.org/stable/c/274f544a32c08638ee887f2e27e3235b6b1237d4
- git.kernel.org/stable/c/12afa450a6a6c0cce2c42b7545a9958f62d8a00c
- git.kernel.org/stable/c/538e67e8c7889cf5f93951f5309d1bcb41f86036
- git.kernel.org/stable/c/8aecf0bbcc72605592134c917c222207d8f63ab0
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON