CVE-2024-45016: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: netem: fix return value if duplicate enqueue fails There is a bug in netem_enqueue() introduced by commit 5845f706388a ("net: netem: fix skb length BUG_ON in __skb_to_sgvec") that can lead to a use-after-free. This commit made netem_enqueue() always return NET_XMIT_SUCCESS when a packet is duplicated, which can cause the parent qdisc's q.qlen to be mistakenly incremented. When this happens qlen_notify() may be skipped on the parent during destruction, leaving a dangling pointer for some classful qdiscs like DRR. There are two ways for the bug happen: - If the duplicated packet is dropped by rootq->enqueue() and then the original packet is also dropped. - If rootq->enqueue() sends the duplicated packet to a different qdisc and the original packet is dropped. In both cases NET_XMIT_SUCCESS is returned even though no packets are enqueued at the netem qdisc. The fix is to defer the enqueue of the duplicate packet until after the original packet has been guaranteed to return NET_XMIT_SUCCESS.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.0 — 5.4.283
linux	linux_kernel	5.5 — 5.10.225
linux	linux_kernel	5.11 — 5.15.166
linux	linux_kernel	5.16 — 6.1.107
linux	linux_kernel	6.2 — 6.6.48
linux	linux_kernel	6.7 — 6.10.7
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/0486d31dd8198e22b63a4730244b38fffce6d469 https://git.kernel.org/stable/c/52d99a69f3d556c6426048c9d481b912205919d8 https://git.kernel.org/stable/c/577d6c0619467fe90f7e8e57e45cb5bd9d936014 https://git.kernel.org/stable/c/759e3e8c4a6a6b4e52ebc4547123a457f0ce90d4 https://git.kernel.org/stable/c/c07ff8592d57ed258afee5a5e04991a48dbaf382 https://git.kernel.org/stable/c/c414000da1c2ea1ba9a5e5bb1a4ba774e51e202d https://git.kernel.org/stable/c/e5bb2988a310667abed66c7d3ffa28880cf0f883

Other References

https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html https://cert-portal.siemens.com/productcert/html/ssa-265688.html

Frequently Asked Questions

What is CVE-2024-45016? +

In the Linux kernel, the following vulnerability has been resolved: netem: fix return value if duplicate enqueue fails There is a bug in netem_enqueue() introduced by commit 5845f706388a ("net: netem: fix skb length BUG_ON in __skb_to_sgvec") that can lead to a use-after-free. This commit made netem_enqueue() always return NET_XMIT_SUCCESS when a packet is duplicated, which can cause the parent qdisc's q.qlen to be mistakenly incremented. When this happens qlen_notify() may be skipped on the parent during destruction, leaving a dangling pointer for some classful qdiscs like DRR. There are two ways for the bug happen: - If the duplicated packet is dropped by rootq->enqueue() and then the original packet is also dropped. - If rootq->enqueue() sends the duplicated packet to a different qdisc and the original packet is dropped. In both cases NET_XMIT_SUCCESS is returned even though no packets are enqueued at the netem qdisc. The fix is to defer the enqueue of the duplicate packet until after the original packet has been guaranteed to return NET_XMIT_SUCCESS. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2024-45016? +

CVE-2024-45016 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-45016? +

CVE-2024-45016 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-2024-45016? +

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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