CyberSecBulletin
CVE-2024-49966NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2024-49966 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 fc5cc716dfbdc5fd5f373ff3b51358174cf88bfc, 89043e7ed63c7fc141e68ea5a79758ed24b6c699, 14114d8148db07e7946fb06b56a50cfa425e26c7 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 0.27% 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 fc5cc716dfbdc5fd5f373ff3b51358174cf88bfc or 89043e7ed63c7fc141e68ea5a79758ed24b6c699 or 14114d8148db07e7946fb06b56a50cfa425e26c7 or 4173d1277c00baeedaaca76783e98b8fd0e3c08d, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.19.323 or 5.4.285 or 5.10.227 or 5.15.168, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, fc5cc716dfbdc5fd5f373ff3b51358174cf88bfc; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, 89043e7ed63c7fc141e68ea5a79758ed24b6c699; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, 14114d8148db07e7946fb06b56a50cfa425e26c7; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, 4173d1277c00baeedaaca76783e98b8fd0e3c08d; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, bbf41277df8b33fbedf4750a9300c147e8f104eb; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, ef768020366f47d23f39c4f57bcb03af6d1e24b3; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, a4346c04d055bf7e184c18a73dbd23b6a9811118; 171bf93ce11f4c9929fdce6ce63df8da2f3c4475 up to, but not including, 0d707a33c84b371cb66120e198eed3374726ddd8; and 2 more rangesfc5cc716dfbdc5fd5f373ff3b51358174cf88bfc, 89043e7ed63c7fc141e68ea5a79758ed24b6c699, 14114d8148db07e7946fb06b56a50cfa425e26c7, 4173d1277c00baeedaaca76783e98b8fd0e3c08d, bbf41277df8b33fbedf4750a9300c147e8f104eb, ef768020366f47d23f39c4f57bcb03af6d1e24b3
DebianDebian Linux11.0Not stated
LinuxLinux Kernel2.6.29 up to, but not including, 4.19.323; 4.20 up to, but not including, 5.4.285; 5.5 up to, but not including, 5.10.227; 5.11 up to, but not including, 5.15.168; 5.16 up to, but not including, 6.1.113; 6.2 up to, but not including, 6.6.55; 6.7 up to, but not including, 6.10.14; 6.11 up to, but not including, 6.11.34.19.323, 5.4.285, 5.10.227, 5.15.168, 6.1.113, 6.6.55

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 systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: cancel dqi_sync_work before freeing oinfo ocfs2_global_read_info() will initialize and schedule dqi_sync_work at the end, if error occurs after successfully reading global quota, it will trigger the following warning with CONFIG_DEBUG_OBJECTS_* enabled: ODEBUG: free active (active state 0) object: 00000000d8b0ce28 object type: timer_list hint: qsync_work_fn+0x0/0x16c This reports that there is an active delayed work when freeing oinfo in error handling, so cancel dqi_sync_work first. BTW, return status instead of -1 when .read_file_info fails.

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: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Use After Free vulnerabilities

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