CVE-2023-4208
Use-after-free in Linux kernel's net/sched: cls_u32 component
- Published
- Updated
- Reserved
- Assigned by
Description
A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation. When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GoogleCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.31% · top 76% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
References (4)
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 (opens in a new tab)patchx_transferred
- https://kernel.dance/3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 (opens in a new tab)x_transferred
- https://www.debian.org/security/2023/dsa-5492 (opens in a new tab)x_transferred
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-4208)Record last updated .