CyberSecBulletin
CVE-2024-27043NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2024-27043 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 d0f5c28333822f9baa5280d813124920720fd856, f20c3270f3ed5aa6919a87e4de9bf6c05fb57086, 096237039d00c839f3e3a5fe6d001bf0db45b644 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 0.29% 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 d0f5c28333822f9baa5280d813124920720fd856 or f20c3270f3ed5aa6919a87e4de9bf6c05fb57086 or 096237039d00c839f3e3a5fe6d001bf0db45b644 or 0d3fe80b6d175c220b3e252efc6c6777e700e98e, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.19.311 or 5.4.273 or 5.10.214 or 5.15.153, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, d0f5c28333822f9baa5280d813124920720fd856; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, f20c3270f3ed5aa6919a87e4de9bf6c05fb57086; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, 096237039d00c839f3e3a5fe6d001bf0db45b644; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, 0d3fe80b6d175c220b3e252efc6c6777e700e98e; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, 437a111f79a2f5b2a5f21e27fdec6f40c8768712; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, 779e8db7efb22316c8581d6c229636d2f5694a62; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, 35674111a043b0482a9bc69da8850a83f465b07d; b61901024776b25ce7b8edc31bb1757c7382a88e up to, but not including, b7586e902128e4fb7bfbb661cb52e4215a65637b; and 2 more rangesd0f5c28333822f9baa5280d813124920720fd856, f20c3270f3ed5aa6919a87e4de9bf6c05fb57086, 096237039d00c839f3e3a5fe6d001bf0db45b644, 0d3fe80b6d175c220b3e252efc6c6777e700e98e, 437a111f79a2f5b2a5f21e27fdec6f40c8768712, 779e8db7efb22316c8581d6c229636d2f5694a62
LinuxLinux Kernel2.6.21 up to, but not including, 4.19.311; 4.20 up to, but not including, 5.4.273; 5.5 up to, but not including, 5.10.214; 5.11 up to, but not including, 5.15.153; 5.16 up to, but not including, 6.1.83; 6.2 up to, but not including, 6.6.23; 6.7 up to, but not including, 6.7.11; 6.8 up to, but not including, 6.8.24.19.311, 5.4.273, 5.10.214, 5.15.153, 6.1.83, 6.6.23

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: media: edia: dvbdev: fix a use-after-free In dvb_register_device, *pdvbdev is set equal to dvbdev, which is freed in several error-handling paths. However, *pdvbdev is not set to NULL after dvbdev's deallocation, causing use-after-frees in many places, for example, in the following call chain: budget_register |-> dvb_dmxdev_init |-> dvb_register_device |-> dvb_dmxdev_release |-> dvb_unregister_device |-> dvb_remove_device |-> dvb_device_put |-> kref_put When calling dvb_unregister_device, dmxdev->dvbdev (i.e. *pdvbdev in dvb_register_device) could point to memory that had been freed in dvb_register_device. Thereafter, this pointer is transferred to kref_put and triggering a use-after-free.

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

Recent Use After Free vulnerabilities

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