CVE-2024-46800: linux kernel Use-After-Free — Fix

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

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.3 — 4.19.322
linux	linux_kernel	4.20 — 5.4.284
linux	linux_kernel	5.5 — 5.10.226
linux	linux_kernel	5.11 — 5.15.167
linux	linux_kernel	5.16 — 6.1.110
linux	linux_kernel	6.2 — 6.6.51
linux	linux_kernel	6.7 — 6.10.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

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

Other References

https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Frequently Asked Questions

What is CVE-2024-46800? +

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 It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2024-46800? +

CVE-2024-46800 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2024-46800? +

CVE-2024-46800 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-46800? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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