Linux: Use After Free
CVE-2022-50252 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 64ca1969599857143e91aeec4440640656100803, 0200f0fbb11e359cc35af72ab10b2ec224e6f633, 68e8adbcaf7a8743e473343b38b9dad66e2ac6f3 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 64ca1969599857143e91aeec4440640656100803 or 0200f0fbb11e359cc35af72ab10b2ec224e6f633 or 68e8adbcaf7a8743e473343b38b9dad66e2ac6f3 or f96bd8adc8adde25390965a8c1ee81b73cb62075, 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 | 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 64ca1969599857143e91aeec4440640656100803; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 0200f0fbb11e359cc35af72ab10b2ec224e6f633; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 68e8adbcaf7a8743e473343b38b9dad66e2ac6f3; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, f96bd8adc8adde25390965a8c1ee81b73cb62075; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 3cb18dea11196fb4a06f78294cec5e61985e1aff; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 314f7092b27749bdde44c14095b5533afa2a3bc8; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 6e399577bd397a517df4b938601108c63769ce0a; 72ddef0506da852dc82f078f37ced8ef4d74a2bf up to, but not including, 56483aecf6b22eb7dff6315b3a174688c6ad494c; and 8 more ranges | 64ca1969599857143e91aeec4440640656100803, 0200f0fbb11e359cc35af72ab10b2ec224e6f633, 68e8adbcaf7a8743e473343b38b9dad66e2ac6f3, f96bd8adc8adde25390965a8c1ee81b73cb62075, 3cb18dea11196fb4a06f78294cec5e61985e1aff, 314f7092b27749bdde44c14095b5533afa2a3bc8 |
| Linux | Linux Kernel | before 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 | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: igb: Do not free q_vector unless new one was allocated Avoid potential use-after-free condition under memory pressure. If the kzalloc() fails, q_vector will be freed but left in the original adapter->q_vector[v_idx] array position.
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/0200f0fbb11e359cc35af72ab10b2ec224e6f633
- git.kernel.org/stable/c/0668716506ca66f90d395f36ccdaebc3e0e84801
- git.kernel.org/stable/c/314f7092b27749bdde44c14095b5533afa2a3bc8
- git.kernel.org/stable/c/3cb18dea11196fb4a06f78294cec5e61985e1aff
- git.kernel.org/stable/c/56483aecf6b22eb7dff6315b3a174688c6ad494c
- git.kernel.org/stable/c/64ca1969599857143e91aeec4440640656100803
- git.kernel.org/stable/c/68e8adbcaf7a8743e473343b38b9dad66e2ac6f3
- git.kernel.org/stable/c/6e399577bd397a517df4b938601108c63769ce0a
- git.kernel.org/stable/c/f96bd8adc8adde25390965a8c1ee81b73cb62075
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
Spotted an error? Tell us.