Linux: Double Free
CVE-2022-49455 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 de65c32ace9aa70d51facc61ba986607075e3a25, ee89d8dee55ab4b3b8ad8b70866b2841ba334767, 8fb674216835e1f0c143762696d645facebb4685 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 0.28% 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 de65c32ace9aa70d51facc61ba986607075e3a25 or ee89d8dee55ab4b3b8ad8b70866b2841ba334767 or 8fb674216835e1f0c143762696d645facebb4685 or 252768d32e92c1214aeebb5fec0844ca479bcf5c, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.198 or 5.10.121 or 5.15.46 or 5.17.14, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 75ca758adbafc81804c39b2c200ecdc819a6c042 up to, but not including, de65c32ace9aa70d51facc61ba986607075e3a25; 75ca758adbafc81804c39b2c200ecdc819a6c042 up to, but not including, ee89d8dee55ab4b3b8ad8b70866b2841ba334767; 75ca758adbafc81804c39b2c200ecdc819a6c042 up to, but not including, 8fb674216835e1f0c143762696d645facebb4685; 75ca758adbafc81804c39b2c200ecdc819a6c042 up to, but not including, 252768d32e92c1214aeebb5fec0844ca479bcf5c; 75ca758adbafc81804c39b2c200ecdc819a6c042 up to, but not including, 9e9087cf34ee69f4e95d146ac29385d6e367a97b; 75ca758adbafc81804c39b2c200ecdc819a6c042 up to, but not including, 950cf957fe34d40d63dfa3bf3968210430b6491e; 5.2 | de65c32ace9aa70d51facc61ba986607075e3a25, ee89d8dee55ab4b3b8ad8b70866b2841ba334767, 8fb674216835e1f0c143762696d645facebb4685, 252768d32e92c1214aeebb5fec0844ca479bcf5c, 9e9087cf34ee69f4e95d146ac29385d6e367a97b, 950cf957fe34d40d63dfa3bf3968210430b6491e |
| Linux | Linux Kernel | 5.2 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 | 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: misc: ocxl: fix possible double free in ocxl_file_register_afu info_release() will be called in device_unregister() when info->dev's reference count is 0. So there is no need to call ocxl_afu_put() and kfree() again. Fix this by adding free_minor() and return to err_unregister error path.
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/252768d32e92c1214aeebb5fec0844ca479bcf5c
- git.kernel.org/stable/c/8fb674216835e1f0c143762696d645facebb4685
- git.kernel.org/stable/c/950cf957fe34d40d63dfa3bf3968210430b6491e
- git.kernel.org/stable/c/9e9087cf34ee69f4e95d146ac29385d6e367a97b
- git.kernel.org/stable/c/de65c32ace9aa70d51facc61ba986607075e3a25
- git.kernel.org/stable/c/ee89d8dee55ab4b3b8ad8b70866b2841ba334767
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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