Linux: Use After Free
CVE-2022-50213 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 77d3b5038b7462318f5183e2ad704b01d57215a2, fab2f61cc3b0e441b1749f017cfee75f9bbaded7, 1a4b18b1ff11ba26f9a852019d674fde9d1d1cff as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 77d3b5038b7462318f5183e2ad704b01d57215a2 or fab2f61cc3b0e441b1749f017cfee75f9bbaded7 or 1a4b18b1ff11ba26f9a852019d674fde9d1d1cff or faafd9286f1355c76fe9ac3021c280297213330e, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.256 or 5.4.211 or 5.10.137 or 5.15.61, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, 77d3b5038b7462318f5183e2ad704b01d57215a2; 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, fab2f61cc3b0e441b1749f017cfee75f9bbaded7; 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, 1a4b18b1ff11ba26f9a852019d674fde9d1d1cff; 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, faafd9286f1355c76fe9ac3021c280297213330e; 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, f4fa03410f7c5f5bd8f90e9c11e9a8c4b526ff6f; 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, 0d07039397527361850c554c192e749cfc879ea9; 958bee14d0718ca7a5002c0f48a099d1d345812a up to, but not including, 470ee20e069a6d05ae549f7d0ef2bdbcee6a81b2; 3.16 | 77d3b5038b7462318f5183e2ad704b01d57215a2, fab2f61cc3b0e441b1749f017cfee75f9bbaded7, 1a4b18b1ff11ba26f9a852019d674fde9d1d1cff, faafd9286f1355c76fe9ac3021c280297213330e, f4fa03410f7c5f5bd8f90e9c11e9a8c4b526ff6f, 0d07039397527361850c554c192e749cfc879ea9 |
| Linux | Linux Kernel | 3.16 up to, but not including, 4.19.256; 4.20 up to, but not including, 5.4.211; 5.5 up to, but not including, 5.10.137; 5.11 up to, but not including, 5.15.61; 5.16 up to, but not including, 5.18.18; 5.19 up to, but not including, 5.19.2 | 4.19.256, 5.4.211, 5.10.137, 5.15.61, 5.18.18, 5.19.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: do not allow SET_ID to refer to another table When doing lookups for sets on the same batch by using its ID, a set from a different table can be used. Then, when the table is removed, a reference to the set may be kept after the set is freed, leading to a potential use-after-free. When looking for sets by ID, use the table that was used for the lookup by name, and only return sets belonging to that same table. This fixes CVE-2022-2586, also reported as ZDI-CAN-17470.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0d07039397527361850c554c192e749cfc879ea9
- git.kernel.org/stable/c/1a4b18b1ff11ba26f9a852019d674fde9d1d1cff
- git.kernel.org/stable/c/470ee20e069a6d05ae549f7d0ef2bdbcee6a81b2
- git.kernel.org/stable/c/77d3b5038b7462318f5183e2ad704b01d57215a2
- git.kernel.org/stable/c/f4fa03410f7c5f5bd8f90e9c11e9a8c4b526ff6f
- git.kernel.org/stable/c/faafd9286f1355c76fe9ac3021c280297213330e
- git.kernel.org/stable/c/fab2f61cc3b0e441b1749f017cfee75f9bbaded7
Recent Use After Free vulnerabilities
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.