Linux: Use After Free
CVE-2022-49114 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 4a131d4ea8b581ac9b01d3a72754db4848be3232, 499d198494e77b6533251b9b909baf5c101129cb, 6044ad64f41c87382cfeeca281573d1886d80cbe 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 0.36% 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 4a131d4ea8b581ac9b01d3a72754db4848be3232 or 499d198494e77b6533251b9b909baf5c101129cb or 6044ad64f41c87382cfeeca281573d1886d80cbe or 5cf2ce8967b0d98c8cfa4dc42ef4fcf080f5c836, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.9.311 or 4.14.276 or 4.19.238 or 5.4.189, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 4a131d4ea8b581ac9b01d3a72754db4848be3232; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 499d198494e77b6533251b9b909baf5c101129cb; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 6044ad64f41c87382cfeeca281573d1886d80cbe; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 5cf2ce8967b0d98c8cfa4dc42ef4fcf080f5c836; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 1d7effe5fff9d28e45e18ac3a564067c7ddfe898; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, f581df412bc45c95176e3c808ee2839c05b2ab0c; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 87909291762d08fdb60d19069d7a89b5b308d0ef; 42e9a92fe6a9095bd68a379aaec7ad2be0337f7a up to, but not including, 412dd8299b02e4410fe77b8396953c1a8dde183a; and 2 more ranges | 4a131d4ea8b581ac9b01d3a72754db4848be3232, 499d198494e77b6533251b9b909baf5c101129cb, 6044ad64f41c87382cfeeca281573d1886d80cbe, 5cf2ce8967b0d98c8cfa4dc42ef4fcf080f5c836, 1d7effe5fff9d28e45e18ac3a564067c7ddfe898, f581df412bc45c95176e3c808ee2839c05b2ab0c |
| Linux | Linux Kernel | before 4.9.311; 4.10 up to, but not including, 4.14.276; 4.15 up to, but not including, 4.19.238; 4.20 up to, but not including, 5.4.189; 5.5 up to, but not including, 5.10.111; 5.11 up to, but not including, 5.15.34; 5.16 up to, but not including, 5.16.20; 5.17 up to, but not including, 5.17.3 | 4.9.311, 4.14.276, 4.19.238, 5.4.189, 5.10.111, 5.15.34 |
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
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: scsi: libfc: Fix use after free in fc_exch_abts_resp() fc_exch_release(ep) will decrease the ep's reference count. When the reference count reaches zero, it is freed. But ep is still used in the following code, which will lead to a use after free. Return after the fc_exch_release() call to avoid use after 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/1d7effe5fff9d28e45e18ac3a564067c7ddfe898
- git.kernel.org/stable/c/271add11994ba1a334859069367e04d2be2ebdd4
- git.kernel.org/stable/c/412dd8299b02e4410fe77b8396953c1a8dde183a
- git.kernel.org/stable/c/499d198494e77b6533251b9b909baf5c101129cb
- git.kernel.org/stable/c/4a131d4ea8b581ac9b01d3a72754db4848be3232
- git.kernel.org/stable/c/5cf2ce8967b0d98c8cfa4dc42ef4fcf080f5c836
- git.kernel.org/stable/c/6044ad64f41c87382cfeeca281573d1886d80cbe
- git.kernel.org/stable/c/87909291762d08fdb60d19069d7a89b5b308d0ef
- git.kernel.org/stable/c/f581df412bc45c95176e3c808ee2839c05b2ab0c
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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