Linux: Double Free
CVE-2022-49410 is a high-severity double 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 f8b383f83cb573152c577eca1ef101e89995b72a, c27f744ceefadc7bbeb14233b6abc150ced617d2, 058cb6d86b9789377216c936506b346aaa1eb581 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 0.3% 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 f8b383f83cb573152c577eca1ef101e89995b72a or c27f744ceefadc7bbeb14233b6abc150ced617d2 or 058cb6d86b9789377216c936506b346aaa1eb581 or 37443b3508b8cce6832f8d25cb4550b2f7801f50, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.247 or 5.4.198 or 5.10.121 or 5.15.46, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, f8b383f83cb573152c577eca1ef101e89995b72a; 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, c27f744ceefadc7bbeb14233b6abc150ced617d2; 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, 058cb6d86b9789377216c936506b346aaa1eb581; 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, 37443b3508b8cce6832f8d25cb4550b2f7801f50; 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, 4fdfb15e08598711dbf50daf56a33965232daf0e; 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, bd83ff3bbfb003832481c9bff999d12385f396ae; 067fe038e70f6e64960d26a79c4df5f1413d0f13 up to, but not including, 99696a2592bca641eb88cc9a80c90e591afebd0f; 4.17 | f8b383f83cb573152c577eca1ef101e89995b72a, c27f744ceefadc7bbeb14233b6abc150ced617d2, 058cb6d86b9789377216c936506b346aaa1eb581, 37443b3508b8cce6832f8d25cb4550b2f7801f50, 4fdfb15e08598711dbf50daf56a33965232daf0e, bd83ff3bbfb003832481c9bff999d12385f396ae |
| Linux | Linux Kernel | 4.17 up to, but not including, 4.19.247; 4.20 up to, but not including, 5.4.198; 5.5 up to, but not including, 5.10.121; 5.11 up to, but not including, 5.15.46; 5.16 up to, but not including, 5.17.14; 5.18 up to, but not including, 5.18.3 | 4.19.247, 5.4.198, 5.10.121, 5.15.46, 5.17.14, 5.18.3 |
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 | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix potential double free in create_var_ref() In create_var_ref(), init_var_ref() is called to initialize the fields of variable ref_field, which is allocated in the previous function call to create_hist_field(). Function init_var_ref() allocates the corresponding fields such as ref_field->system, but frees these fields when the function encounters an error. The caller later calls destroy_hist_field() to conduct error handling, which frees the fields and the variable itself. This results in double free of the fields which are already freed in the previous function. Fix this by storing NULL to the corresponding fields when they are freed in init_var_ref().
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
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/058cb6d86b9789377216c936506b346aaa1eb581
- git.kernel.org/stable/c/37443b3508b8cce6832f8d25cb4550b2f7801f50
- git.kernel.org/stable/c/4fdfb15e08598711dbf50daf56a33965232daf0e
- git.kernel.org/stable/c/99696a2592bca641eb88cc9a80c90e591afebd0f
- git.kernel.org/stable/c/bd83ff3bbfb003832481c9bff999d12385f396ae
- git.kernel.org/stable/c/c27f744ceefadc7bbeb14233b6abc150ced617d2
- git.kernel.org/stable/c/f8b383f83cb573152c577eca1ef101e89995b72a
Recent Double 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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