Linux: Use After Free
CVE-2022-48695 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 b8fc9e91b931215110ba824d1a2983c5f60b6f82, d4959d09b76eb7a4146f5133962b88d3bddb63d6, 82efb917eeb27454dc4c6fe26432fc8f6c75bc16 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 0.24% 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 b8fc9e91b931215110ba824d1a2983c5f60b6f82 or d4959d09b76eb7a4146f5133962b88d3bddb63d6 or 82efb917eeb27454dc4c6fe26432fc8f6c75bc16 or 5682c94644fde72f72bded6580c38189ffc856b5, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.9.328 or 4.14.293 or 4.19.258 or 5.4.213, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, b8fc9e91b931215110ba824d1a2983c5f60b6f82; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, d4959d09b76eb7a4146f5133962b88d3bddb63d6; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, 82efb917eeb27454dc4c6fe26432fc8f6c75bc16; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, 5682c94644fde72f72bded6580c38189ffc856b5; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, ea10a652ad2ae2cf3eced6f632a5c98f26727057; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, 6229fa494a5949be209bc73afbc5d0a749c2e3c7; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, 41acb064c4e013808bc7d5fc1b506fa449425b0b; 146b16c8071f5f6c67895d15beeee1163f5107c4 up to, but not including, 991df3dd5144f2e6b1c38b8d20ed3d4d21e20b34; and 1 more ranges | b8fc9e91b931215110ba824d1a2983c5f60b6f82, d4959d09b76eb7a4146f5133962b88d3bddb63d6, 82efb917eeb27454dc4c6fe26432fc8f6c75bc16, 5682c94644fde72f72bded6580c38189ffc856b5, ea10a652ad2ae2cf3eced6f632a5c98f26727057, 6229fa494a5949be209bc73afbc5d0a749c2e3c7 |
| Linux | Linux Kernel | before 4.9.328; 4.10 up to, but not including, 4.14.293; 4.15 up to, but not including, 4.19.258; 4.20 up to, but not including, 5.4.213; 5.5 up to, but not including, 5.10.143; 5.11 up to, but not including, 5.15.168; 5.16 up to, but not including, 5.19.9; 6.0 | 4.9.328, 4.14.293, 4.19.258, 5.4.213, 5.10.143, 5.15.168 |
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: scsi: mpt3sas: Fix use-after-free warning Fix the following use-after-free warning which is observed during controller reset: refcount_t: underflow; use-after-free. WARNING: CPU: 23 PID: 5399 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/41acb064c4e013808bc7d5fc1b506fa449425b0b
- git.kernel.org/stable/c/5682c94644fde72f72bded6580c38189ffc856b5
- git.kernel.org/stable/c/6229fa494a5949be209bc73afbc5d0a749c2e3c7
- git.kernel.org/stable/c/82efb917eeb27454dc4c6fe26432fc8f6c75bc16
- git.kernel.org/stable/c/991df3dd5144f2e6b1c38b8d20ed3d4d21e20b34
- git.kernel.org/stable/c/b8fc9e91b931215110ba824d1a2983c5f60b6f82
- git.kernel.org/stable/c/d4959d09b76eb7a4146f5133962b88d3bddb63d6
- git.kernel.org/stable/c/ea10a652ad2ae2cf3eced6f632a5c98f26727057
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.4 High severity
- 9.8 Critical severity
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