Linux: Use After Free
CVE-2022-50384 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 5cc4eea715a3fcf4e516662f736dfee63979465f, 51c0ad3b7c5b01f9314758335a13f157b05fa56d, e6b0adff99edf246ba1f8d464530a0438cb1cbda 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 0.17% 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 5cc4eea715a3fcf4e516662f736dfee63979465f or 51c0ad3b7c5b01f9314758335a13f157b05fa56d or e6b0adff99edf246ba1f8d464530a0438cb1cbda or a45ba33d398a821147d7e5f16ead7eb125e331e2, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.9.337 or 4.14.303 or 4.19.270 or 5.4.229, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, 5cc4eea715a3fcf4e516662f736dfee63979465f; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, 51c0ad3b7c5b01f9314758335a13f157b05fa56d; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, e6b0adff99edf246ba1f8d464530a0438cb1cbda; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, a45ba33d398a821147d7e5f16ead7eb125e331e2; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, 5d2b286eb034af114f67d9967fc3fbc1829bb712; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, 1f5661388f43df3ac106ce93e67d8d22b16a78ff; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, cf138759a7e92c75cfc1b7ba705e4108fe330edf; b2383c90a9d691201b9aee557776694cde86a935 up to, but not including, 85db68fc901da52314ded80aace99f8b684c7815; and 2 more ranges | 5cc4eea715a3fcf4e516662f736dfee63979465f, 51c0ad3b7c5b01f9314758335a13f157b05fa56d, e6b0adff99edf246ba1f8d464530a0438cb1cbda, a45ba33d398a821147d7e5f16ead7eb125e331e2, 5d2b286eb034af114f67d9967fc3fbc1829bb712, 1f5661388f43df3ac106ce93e67d8d22b16a78ff |
| Linux | Linux Kernel | 4.2 up to, but not including, 4.9.337; 4.10 up to, but not including, 4.14.303; 4.15 up to, but not including, 4.19.270; 4.20 up to, but not including, 5.4.229; 5.5 up to, but not including, 5.10.163; 5.11 up to, but not including, 5.15.86; 5.16 up to, but not including, 6.0.16; 6.1 up to, but not including, 6.1.2 | 4.9.337, 4.14.303, 4.19.270, 5.4.229, 5.10.163, 5.15.86 |
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 | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: staging: vme_user: Fix possible UAF in tsi148_dma_list_add Smatch report warning as follows: drivers/staging/vme_user/vme_tsi148.c:1757 tsi148_dma_list_add() warn: '&entry->list' not removed from list In tsi148_dma_list_add(), the error path "goto err_dma" will not remove entry->list from list->entries, but entry will be freed, then list traversal may cause UAF. Fix by removeing it from list->entries before free().
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1f5661388f43df3ac106ce93e67d8d22b16a78ff
- git.kernel.org/stable/c/357057ee55d3c99a5de5abe8150f7bca04f8e53b
- git.kernel.org/stable/c/51c0ad3b7c5b01f9314758335a13f157b05fa56d
- git.kernel.org/stable/c/5cc4eea715a3fcf4e516662f736dfee63979465f
- git.kernel.org/stable/c/5d2b286eb034af114f67d9967fc3fbc1829bb712
- git.kernel.org/stable/c/85db68fc901da52314ded80aace99f8b684c7815
- git.kernel.org/stable/c/a45ba33d398a821147d7e5f16ead7eb125e331e2
- git.kernel.org/stable/c/cf138759a7e92c75cfc1b7ba705e4108fe330edf
- git.kernel.org/stable/c/e6b0adff99edf246ba1f8d464530a0438cb1cbda
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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