CyberSecBulletin
CVE-2022-49385NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2022-49385 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 5d709f58c743166fe1c6914b9de0ae8868600d9b, 823f24f2e329babd0330200d0b74882516fe57f4, cdf1a683a01583bca4b618dd16223cbd6e462e21 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.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 5d709f58c743166fe1c6914b9de0ae8868600d9b or 823f24f2e329babd0330200d0b74882516fe57f4 or cdf1a683a01583bca4b618dd16223cbd6e462e21 or 5389101257828d1913d713d9a40acbe14f5961df, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.4.198 or 5.10.122 or 5.15.47 or 5.17.15, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux190888ac01d059e38ffe77a2291d44cafa9016fb up to, but not including, 5d709f58c743166fe1c6914b9de0ae8868600d9b; 190888ac01d059e38ffe77a2291d44cafa9016fb up to, but not including, 823f24f2e329babd0330200d0b74882516fe57f4; 190888ac01d059e38ffe77a2291d44cafa9016fb up to, but not including, cdf1a683a01583bca4b618dd16223cbd6e462e21; 190888ac01d059e38ffe77a2291d44cafa9016fb up to, but not including, 5389101257828d1913d713d9a40acbe14f5961df; 190888ac01d059e38ffe77a2291d44cafa9016fb up to, but not including, c059665c84feab46b7173d3a1bf36c2fb7f9df86; 190888ac01d059e38ffe77a2291d44cafa9016fb up to, but not including, 310862e574001a97ad02272bac0fd13f75f42a27; 3.95d709f58c743166fe1c6914b9de0ae8868600d9b, 823f24f2e329babd0330200d0b74882516fe57f4, cdf1a683a01583bca4b618dd16223cbd6e462e21, 5389101257828d1913d713d9a40acbe14f5961df, c059665c84feab46b7173d3a1bf36c2fb7f9df86, 310862e574001a97ad02272bac0fd13f75f42a27
LinuxLinux Kernel3.9 up to, but not including, 5.4.198; 5.5 up to, but not including, 5.10.122; 5.11 up to, but not including, 5.15.47; 5.16 up to, but not including, 5.17.15; 5.18 up to, but not including, 5.18.45.4.198, 5.10.122, 5.15.47, 5.17.15, 5.18.4

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 CISA (ADP).

Official description

In the Linux kernel, the following vulnerability has been resolved: driver: base: fix UAF when driver_attach failed When driver_attach(drv); failed, the driver_private will be freed. But it has been added to the bus, which caused a UAF. To fix it, we need to delete it from the bus when failed.

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.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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