Linux: Use After Free
CVE-2022-49811 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 fc1897f16ebcfd22364f2afcc27f53a740f3bc7a, bf47ca1b35fc1f55091ffaff5fbe41ea0c6f59a1, 813a8dd9c45fd46f5cbbfbedf0791afa7740ccf5 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 fc1897f16ebcfd22364f2afcc27f53a740f3bc7a or bf47ca1b35fc1f55091ffaff5fbe41ea0c6f59a1 or 813a8dd9c45fd46f5cbbfbedf0791afa7740ccf5 or 9ed51414aef6e59e832e2960f10766dce2d5b1a1, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.300 or 4.19.267 or 5.4.225 or 5.10.156, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, fc1897f16ebcfd22364f2afcc27f53a740f3bc7a; b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, bf47ca1b35fc1f55091ffaff5fbe41ea0c6f59a1; b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, 813a8dd9c45fd46f5cbbfbedf0791afa7740ccf5; b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, 9ed51414aef6e59e832e2960f10766dce2d5b1a1; b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, 7d93417d596402ddd46bd76c721f205d09d0d025; b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, c2a00b149836d60c222930bbea6b2139caf34d4f; b6f85ef9538b2111a8ba0bbfae9aaebabfc94961 up to, but not including, a7a1598189228b5007369a9622ccdf587be0730f; 3.15 | fc1897f16ebcfd22364f2afcc27f53a740f3bc7a, bf47ca1b35fc1f55091ffaff5fbe41ea0c6f59a1, 813a8dd9c45fd46f5cbbfbedf0791afa7740ccf5, 9ed51414aef6e59e832e2960f10766dce2d5b1a1, 7d93417d596402ddd46bd76c721f205d09d0d025, c2a00b149836d60c222930bbea6b2139caf34d4f |
| Linux | Linux Kernel | 3.15 up to, but not including, 4.14.300; 4.15 up to, but not including, 4.19.267; 4.20 up to, but not including, 5.4.225; 5.5 up to, but not including, 5.10.156; 5.11 up to, but not including, 5.15.80; 5.16 up to, but not including, 6.0.10; 6.1 | 4.14.300, 4.19.267, 5.4.225, 5.10.156, 5.15.80, 6.0.10 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: drbd: use after free in drbd_create_device() The drbd_destroy_connection() frees the "connection" so use the _safe() iterator to prevent a 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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/7d93417d596402ddd46bd76c721f205d09d0d025
- git.kernel.org/stable/c/813a8dd9c45fd46f5cbbfbedf0791afa7740ccf5
- git.kernel.org/stable/c/9ed51414aef6e59e832e2960f10766dce2d5b1a1
- git.kernel.org/stable/c/a7a1598189228b5007369a9622ccdf587be0730f
- git.kernel.org/stable/c/bf47ca1b35fc1f55091ffaff5fbe41ea0c6f59a1
- git.kernel.org/stable/c/c2a00b149836d60c222930bbea6b2139caf34d4f
- git.kernel.org/stable/c/fc1897f16ebcfd22364f2afcc27f53a740f3bc7a
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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