CyberSecBulletin
CVE-2023-52847NVD status: Modified

Linux: Concurrent Execution using Shared Resource with Improper Synchronization

Published Updated By the CyberSecBulletin desk

CVE-2023-52847 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 bbc3b8dd2cb7817e703f112d988e4f4728f0f2a9, b35fdade92c5058a5e727e233fe263b828de2c9a, 2f3d9198cdae1cb079ec8652f4defacd481eab2b 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 0.19% 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 bbc3b8dd2cb7817e703f112d988e4f4728f0f2a9 or b35fdade92c5058a5e727e233fe263b828de2c9a or 2f3d9198cdae1cb079ec8652f4defacd481eab2b or 51c94256a83fe4e17406c66ff3e1ad7d242d8574, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.19.299 or 5.4.261 or 5.10.201 or 5.15.139, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, bbc3b8dd2cb7817e703f112d988e4f4728f0f2a9; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, b35fdade92c5058a5e727e233fe263b828de2c9a; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, 2f3d9198cdae1cb079ec8652f4defacd481eab2b; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, 51c94256a83fe4e17406c66ff3e1ad7d242d8574; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, 20568d06f6069cb835e05eed432edf962645d226; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, 1871014d6ef4812ad11ef7d838d73ce09d632267; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, 847599fffa528b2cdec4e21b6bf7586dad982132; 162e6376ac58440beb6a2d2ee294f5d88ea58dd1 up to, but not including, bd5b50b329e850d467e7bcc07b2b6bde3752fbda; and 1 more rangesbbc3b8dd2cb7817e703f112d988e4f4728f0f2a9, b35fdade92c5058a5e727e233fe263b828de2c9a, 2f3d9198cdae1cb079ec8652f4defacd481eab2b, 51c94256a83fe4e17406c66ff3e1ad7d242d8574, 20568d06f6069cb835e05eed432edf962645d226, 1871014d6ef4812ad11ef7d838d73ce09d632267
LinuxLinux Kernel4.15 up to, but not including, 4.19.299; 4.20 up to, but not including, 5.4.261; 5.5 up to, but not including, 5.10.201; 5.11 up to, but not including, 5.15.139; 5.16 up to, but not including, 6.1.63; 6.2 up to, but not including, 6.5.12; 6.6 up to, but not including, 6.6.24.19.299, 5.4.261, 5.10.201, 5.15.139, 6.1.63, 6.5.12

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
HighSuccess depends on conditions outside the attacker's control.
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:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.0HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: media: bttv: fix use after free error due to btv->timeout timer There may be some a race condition between timer function bttv_irq_timeout and bttv_remove. The timer is setup in probe and there is no timer_delete operation in remove function. When it hit kfree btv, the function might still be invoked, which will cause use after free bug. This bug is found by static analysis, it may be false positive. Fix it by adding del_timer_sync invoking to the remove function. cpu0 cpu1 bttv_probe ->timer_setup ->bttv_set_dma ->mod_timer; bttv_remove ->kfree(btv); ->bttv_irq_timeout ->USE btv

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How developers prevent this class of flaw

  • In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
  • Use thread-safe capabilities such as the data access abstraction in Spring.
  • Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).

More Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities (CWE-362)

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 Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities

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