CVE-2022-48988
memcg: fix possible use-after-free in memcg_write_event_control()
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: memcg: fix possible use-after-free in memcg_write_event_control() memcg_write_event_control() accesses the dentry->d_name of the specified control fd to route the write call. As a cgroup interface file can't be renamed, it's safe to access d_name as long as the specified file is a regular cgroup file. Also, as these cgroup interface files can't be removed before the directory, it's safe to access the parent too. Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a call to __file_cft() which verified that the specified file is a regular cgroupfs file before further accesses. The cftype pointer returned from __file_cft() was no longer necessary and the commit inadvertently dropped the file type check with it allowing any file to slip through. With the invarients broken, the d_name and parent accesses can now race against renames and removals of arbitrary files and cause use-after-free's. Fix the bug by resurrecting the file type check in __file_cft(). Now that cgroupfs is implemented through kernfs, checking the file operations needs to go through a layer of indirection. Instead, let's check the superblock and dentry type.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (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 | High7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.24% · top 84% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
- affected 347c4a8747104a945ecced358944e42879176ca5 – < b77600e26fd48727a95ffd50ba1e937efb548125
- affected 347c4a8747104a945ecced358944e42879176ca5 – < e1ae97624ecf400ea56c238bff23e5cd139df0b8
- affected 347c4a8747104a945ecced358944e42879176ca5 – < 35963b31821920908e397146502066f6b032c917
- affected 347c4a8747104a945ecced358944e42879176ca5 – < f1f7f36cf682fa59db15e2089039a2eeb58ff2ad
- affected 347c4a8747104a945ecced358944e42879176ca5 – < aad8bbd17a1d586005feb9226c2e9cfce1432e13
- affected 347c4a8747104a945ecced358944e42879176ca5 – < 0ed074317b835caa6c03bcfa8f133365324673dc
- affected 347c4a8747104a945ecced358944e42879176ca5 – < 4a7ba45b1a435e7097ca0f79a847d0949d0eb088
- affected 3.14
- unaffected < 3.14
- unaffected 4.14.302 – ≤ 4.14.*
- unaffected 4.19.269 – ≤ 4.19.*
- unaffected 5.4.227 – ≤ 5.4.*
- unaffected 5.10.159 – ≤ 5.10.*
- unaffected 5.15.83 – ≤ 5.15.*
- unaffected 6.0.13 – ≤ 6.0.*
- unaffected 6.1 – ≤ *
References (7)
- https://git.kernel.org/stable/c/b77600e26fd48727a95ffd50ba1e937efb548125 (opens in a new tab)
- https://git.kernel.org/stable/c/e1ae97624ecf400ea56c238bff23e5cd139df0b8 (opens in a new tab)
- https://git.kernel.org/stable/c/35963b31821920908e397146502066f6b032c917 (opens in a new tab)
- https://git.kernel.org/stable/c/f1f7f36cf682fa59db15e2089039a2eeb58ff2ad (opens in a new tab)
- https://git.kernel.org/stable/c/aad8bbd17a1d586005feb9226c2e9cfce1432e13 (opens in a new tab)
- https://git.kernel.org/stable/c/0ed074317b835caa6c03bcfa8f133365324673dc (opens in a new tab)
- https://git.kernel.org/stable/c/4a7ba45b1a435e7097ca0f79a847d0949d0eb088 (opens in a new tab)
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-2022-48988)Record last updated .