Linux: Double Free
CVE-2022-49508 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 c92ec22a991778a096342cf1a917ae36c5c86a90, f1d4f19a796551edc6679a681ea1756b8c578c08, 6d0726725c7c560495f5ff364862a2cefea542e3 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 c92ec22a991778a096342cf1a917ae36c5c86a90 or f1d4f19a796551edc6679a681ea1756b8c578c08 or 6d0726725c7c560495f5ff364862a2cefea542e3 or 24f9dfdaece9bd75bb8dbfdba83eddeefdf7dc47, 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 | 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, c92ec22a991778a096342cf1a917ae36c5c86a90; 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, f1d4f19a796551edc6679a681ea1756b8c578c08; 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, 6d0726725c7c560495f5ff364862a2cefea542e3; 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, 24f9dfdaece9bd75bb8dbfdba83eddeefdf7dc47; 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, 5291451851feeb66fd4bf0826710f482f3b1ab38; 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, 8bb1716507ebf12d50bbf181764481de3b6bc7fd; 9a6a4193d65b853020ef0e66cecdf9e64a863883 up to, but not including, 1af20714fedad238362571620be0bd690ded05b6; 4.17 | c92ec22a991778a096342cf1a917ae36c5c86a90, f1d4f19a796551edc6679a681ea1756b8c578c08, 6d0726725c7c560495f5ff364862a2cefea542e3, 24f9dfdaece9bd75bb8dbfdba83eddeefdf7dc47, 5291451851feeb66fd4bf0826710f482f3b1ab38, 8bb1716507ebf12d50bbf181764481de3b6bc7fd |
| 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: HID: elan: Fix potential double free in elan_input_configured 'input' is a managed resource allocated with devm_input_allocate_device(), so there is no need to call input_free_device() explicitly or there will be a double free. According to the doc of devm_input_allocate_device(): * Managed input devices do not need to be explicitly unregistered or * freed as it will be done automatically when owner device unbinds from * its driver (or binding fails).
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/1af20714fedad238362571620be0bd690ded05b6
- git.kernel.org/stable/c/24f9dfdaece9bd75bb8dbfdba83eddeefdf7dc47
- git.kernel.org/stable/c/5291451851feeb66fd4bf0826710f482f3b1ab38
- git.kernel.org/stable/c/6d0726725c7c560495f5ff364862a2cefea542e3
- git.kernel.org/stable/c/8bb1716507ebf12d50bbf181764481de3b6bc7fd
- git.kernel.org/stable/c/c92ec22a991778a096342cf1a917ae36c5c86a90
- git.kernel.org/stable/c/f1d4f19a796551edc6679a681ea1756b8c578c08
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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