Linux: Double Free
CVE-2022-50499 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 0588b12c418c3e4f927ced11f27b02ef4a5bfb07, e9a78485b658361fab6a5547377be6c1af6f1b3d, 70bc51303871159796b55ba1a8f16637b46c2511 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 0588b12c418c3e4f927ced11f27b02ef4a5bfb07 or e9a78485b658361fab6a5547377be6c1af6f1b3d or 70bc51303871159796b55ba1a8f16637b46c2511 or b21f62b49ee9c3e0216d685d9cfd6003e5727271, 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 5.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 9db28659aa893c68f162b11fd63bb7f6a713e52f up to, but not including, 0588b12c418c3e4f927ced11f27b02ef4a5bfb07; 1399a136127bfe1b9bb7c951d9851da62a519121 up to, but not including, e9a78485b658361fab6a5547377be6c1af6f1b3d; 4df2427a5148093987437054bb82da4d014dcd59 up to, but not including, 70bc51303871159796b55ba1a8f16637b46c2511; fcd5ce4b3936242e6679875a4d3c3acfc8743e15 up to, but not including, b21f62b49ee9c3e0216d685d9cfd6003e5727271; fcd5ce4b3936242e6679875a4d3c3acfc8743e15 up to, but not including, 7dd5a68cdbbbe7fc67ba701cb52ba10d8ba149f8; fcd5ce4b3936242e6679875a4d3c3acfc8743e15 up to, but not including, acf984a3718c2458eb9e08b6714490a04f213c58; fcd5ce4b3936242e6679875a4d3c3acfc8743e15 up to, but not including, 772892b29ac50c2c5e918fc80104aa6ede81d837; fcd5ce4b3936242e6679875a4d3c3acfc8743e15 up to, but not including, 123eddf92a114e03919942641d2c2b1f4ca56ea6; and 9 more ranges | 0588b12c418c3e4f927ced11f27b02ef4a5bfb07, e9a78485b658361fab6a5547377be6c1af6f1b3d, 70bc51303871159796b55ba1a8f16637b46c2511, b21f62b49ee9c3e0216d685d9cfd6003e5727271, 7dd5a68cdbbbe7fc67ba701cb52ba10d8ba149f8, acf984a3718c2458eb9e08b6714490a04f213c58 |
| Linux | Linux Kernel | 4.9.195 up to, but not including, 4.9.337; 4.14.147 up to, but not including, 4.14.303; 4.19.77 up to, but not including, 4.19.270; 5.2.19 up to, but not including, 5.3; 5.3.4 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, 5.15.87; 5.16 up to, but not including, 6.0.18; and 1 more ranges | 4.9.337, 4.14.303, 4.19.270, 5.3, 5.4.229, 5.10.163 |
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: media: dvb-core: Fix double free in dvb_register_device() In function dvb_register_device() -> dvb_register_media_device() -> dvb_create_media_entity(), dvb->entity is allocated and initialized. If the initialization fails, it frees the dvb->entity, and return an error code. The caller takes the error code and handles the error by calling dvb_media_device_free(), which unregisters the entity and frees the field again if it is not NULL. As dvb->entity may not NULLed in dvb_create_media_entity() when the allocation of dvbdev->pad fails, a double free may occur. This may also cause an Use After free in media_device_unregister_entity(). Fix this by storing NULL to dvb->entity when it is freed.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0588b12c418c3e4f927ced11f27b02ef4a5bfb07
- git.kernel.org/stable/c/123eddf92a114e03919942641d2c2b1f4ca56ea6
- git.kernel.org/stable/c/6b0d0477fce747d4137aa65856318b55fba72198
- git.kernel.org/stable/c/70bc51303871159796b55ba1a8f16637b46c2511
- git.kernel.org/stable/c/772892b29ac50c2c5e918fc80104aa6ede81d837
- git.kernel.org/stable/c/7dd5a68cdbbbe7fc67ba701cb52ba10d8ba149f8
- git.kernel.org/stable/c/acf984a3718c2458eb9e08b6714490a04f213c58
- git.kernel.org/stable/c/b21f62b49ee9c3e0216d685d9cfd6003e5727271
- git.kernel.org/stable/c/e9a78485b658361fab6a5547377be6c1af6f1b3d
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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