CyberSecBulletin
CVE-2024-50269NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2024-50269 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 721ddad945596220c123eb6f7126729fe277ee4f, 4aa77d5ea9944468e16c3eed15e858fd5de44de1, 6e2848d1c8c0139161e69ac0a94133e90e9988e8 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 721ddad945596220c123eb6f7126729fe277ee4f or 4aa77d5ea9944468e16c3eed15e858fd5de44de1 or 6e2848d1c8c0139161e69ac0a94133e90e9988e8 or 63559ba8077cbadae1c92a65b73ea522bf377dd9, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.5 or 4.10 or 4.14 or 4.19.324, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, 721ddad945596220c123eb6f7126729fe277ee4f; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, 4aa77d5ea9944468e16c3eed15e858fd5de44de1; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, 6e2848d1c8c0139161e69ac0a94133e90e9988e8; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, 63559ba8077cbadae1c92a65b73ea522bf377dd9; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, ccd811c304d2ee56189bfbc49302cb3c44361893; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, 8a30da5aa9609663b3e05bcc91a916537f66a4cd; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, b08baa75b989cf779cbfa0969681f8ba2dc46569; 6ed05c68cbcae42cd52b8e53b66952bfa9c002ce up to, but not including, 498dbd9aea205db9da674994b74c7bf8e18448bd; and 7 more ranges721ddad945596220c123eb6f7126729fe277ee4f, 4aa77d5ea9944468e16c3eed15e858fd5de44de1, 6e2848d1c8c0139161e69ac0a94133e90e9988e8, 63559ba8077cbadae1c92a65b73ea522bf377dd9, ccd811c304d2ee56189bfbc49302cb3c44361893, 8a30da5aa9609663b3e05bcc91a916537f66a4cd
LinuxLinux Kernel4.4.95 up to, but not including, 4.5; 4.9.59 up to, but not including, 4.10; 4.13.10 up to, but not including, 4.14; 4.14 up to, but not including, 4.19.324; 4.20 up to, but not including, 5.4.286; 5.5 up to, but not including, 5.10.230; 5.11 up to, but not including, 5.15.172; 5.16 up to, but not including, 6.1.117; and 3 more ranges4.5, 4.10, 4.14, 4.19.324, 5.4.286, 5.10.230

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 3.17.8HighNVD
CVSS 3.17.8HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: musb: sunxi: Fix accessing an released usb phy Commit 6ed05c68cbca ("usb: musb: sunxi: Explicitly release USB PHY on exit") will cause that usb phy @glue->xceiv is accessed after released. 1) register platform driver @sunxi_musb_driver // get the usb phy @glue->xceiv sunxi_musb_probe() -> devm_usb_get_phy(). 2) register and unregister platform driver @musb_driver musb_probe() -> sunxi_musb_init() use the phy here //the phy is released here musb_remove() -> sunxi_musb_exit() -> devm_usb_put_phy() 3) register @musb_driver again musb_probe() -> sunxi_musb_init() use the phy here but the phy has been released at 2). ... Fixed by reverting the commit, namely, removing devm_usb_put_phy() from sunxi_musb_exit().

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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