Linux: Use After Free
CVE-2022-48754 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 67d271760b037ce0806d687ee6057edc8afd4205, f39027cbada43b33566c312e6be3db654ca3ad17, bd024e36f68174b1793906c39ca16cee0c9295c2 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 0.23% 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 67d271760b037ce0806d687ee6057edc8afd4205 or f39027cbada43b33566c312e6be3db654ca3ad17 or bd024e36f68174b1793906c39ca16cee0c9295c2 or aefaccd19379d6c4620269a162bfb88ff687f289, whichever matches your release line, or a later version.
- Update linux_kernel to 67d271760b03 or f39027cbada4 or bd024e36f681 or aefaccd19379, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | bafbdd527d569c8200521f2f7579f65a044271be up to, but not including, 67d271760b037ce0806d687ee6057edc8afd4205; bafbdd527d569c8200521f2f7579f65a044271be up to, but not including, f39027cbada43b33566c312e6be3db654ca3ad17; bafbdd527d569c8200521f2f7579f65a044271be up to, but not including, bd024e36f68174b1793906c39ca16cee0c9295c2; bafbdd527d569c8200521f2f7579f65a044271be up to, but not including, aefaccd19379d6c4620269a162bfb88ff687f289; bafbdd527d569c8200521f2f7579f65a044271be up to, but not including, cb2fab10fc5e7a3aa1bb0a68a3abdcf3e37852af; bafbdd527d569c8200521f2f7579f65a044271be up to, but not including, cbda1b16687580d5beee38273f6241ae3725960c; 4.16 | 67d271760b037ce0806d687ee6057edc8afd4205, f39027cbada43b33566c312e6be3db654ca3ad17, bd024e36f68174b1793906c39ca16cee0c9295c2, aefaccd19379d6c4620269a162bfb88ff687f289, cb2fab10fc5e7a3aa1bb0a68a3abdcf3e37852af, cbda1b16687580d5beee38273f6241ae3725960c |
| Linux | linux_kernel | bafbdd527d56 up to, but not including, 67d271760b03; bafbdd527d56 up to, but not including, f39027cbada4; bafbdd527d56 up to, but not including, bd024e36f681; bafbdd527d56 up to, but not including, aefaccd19379; bafbdd527d56 up to, but not including, cb2fab10fc5e; bafbdd527d56 up to, but not including, cbda1b166875; 4.16 | 67d271760b03, f39027cbada4, bd024e36f681, aefaccd19379, cb2fab10fc5e, cbda1b166875 |
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 CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 8.4 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: phylib: fix potential use-after-free Commit bafbdd527d56 ("phylib: Add device reset GPIO support") added call to phy_device_reset(phydev) after the put_device() call in phy_detach(). The comment before the put_device() call says that the phydev might go away with put_device(). Fix potential use-after-free by calling phy_device_reset() before put_device().
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/67d271760b037ce0806d687ee6057edc8afd4205
- git.kernel.org/stable/c/aefaccd19379d6c4620269a162bfb88ff687f289
- git.kernel.org/stable/c/bd024e36f68174b1793906c39ca16cee0c9295c2
- git.kernel.org/stable/c/cb2fab10fc5e7a3aa1bb0a68a3abdcf3e37852af
- git.kernel.org/stable/c/cbda1b16687580d5beee38273f6241ae3725960c
- git.kernel.org/stable/c/f39027cbada43b33566c312e6be3db654ca3ad17
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
- 8.8 High severity
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