CyberSecBulletin
CVE-2024-27020NVD status: Modified

Linux: Concurrent Execution using Shared Resource with Improper Synchronization

Published Updated By the CyberSecBulletin desk

CVE-2024-27020 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 939109c0a8e2a006a6cc8209e262d25065f4403a, b38a133d37fa421c8447b383d788c9cc6f5cb34c, 934e66e231cff2b18faa2c8aad0b8cec13957e05 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 0.22% 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 939109c0a8e2a006a6cc8209e262d25065f4403a or b38a133d37fa421c8447b383d788c9cc6f5cb34c or 934e66e231cff2b18faa2c8aad0b8cec13957e05 or 0b6de00206adbbfc6373b3ae38d2a6f197987907, whichever matches your release line, or a later version.
  2. Update RUGGEDCOM RST2428P to V3.1 or a later version.
  3. Update SCALANCE XCM-/XRM-/XCH-/XRH-300 family to V3.1 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, 939109c0a8e2a006a6cc8209e262d25065f4403a; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, b38a133d37fa421c8447b383d788c9cc6f5cb34c; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, 934e66e231cff2b18faa2c8aad0b8cec13957e05; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, 0b6de00206adbbfc6373b3ae38d2a6f197987907; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, 8d56bad42ac4c43c6c72ddd6a654a2628bf839c5; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, a9ebf340d123ae12582210407f879d6a5a1bc25b; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, 01f1a678b05ade4b1248019c2dcca773aebbeb7f; ef1f7df9170dbd875ce198ba84e6ab80f6fc139e up to, but not including, f969eb84ce482331a991079ab7a5c4dc3b7f89bf; and 1 more ranges939109c0a8e2a006a6cc8209e262d25065f4403a, b38a133d37fa421c8447b383d788c9cc6f5cb34c, 934e66e231cff2b18faa2c8aad0b8cec13957e05, 0b6de00206adbbfc6373b3ae38d2a6f197987907, 8d56bad42ac4c43c6c72ddd6a654a2628bf839c5, a9ebf340d123ae12582210407f879d6a5a1bc25b
SiemensRUGGEDCOM RST2428Pbefore V3.1V3.1
SiemensSCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 familyNot specified in the recordNot stated
SiemensSCALANCE XCM-/XRM-/XCH-/XRH-300 familybefore V3.1V3.1
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.0 up to, but not including, V3.1.5V3.1.5
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.0 up to, but not including, V3.1.5V3.1.5
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystembefore V1.1.1V1.1.1
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.0 up to, but not including, V3.1.5V3.1.5
LinuxLinux Kernel3.13 up to, but not including, 4.19.313; 4.20 up to, but not including, 5.4.275; 5.5 up to, but not including, 5.10.216; 5.11 up to, but not including, 5.15.157; 5.16 up to, but not including, 6.1.88; 6.2 up to, but not including, 6.6.29; 6.7 up to, but not including, 6.8.8; 6.94.19.313, 5.4.275, 5.10.216, 5.15.157, 6.1.88, 6.6.29

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
CVSS 3.17.0HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get() nft_unregister_expr() can concurrent with __nft_expr_type_get(), and there is not any protection when iterate over nf_tables_expressions list in __nft_expr_type_get(). Therefore, there is potential data-race of nf_tables_expressions list entry. Use list_for_each_entry_rcu() to iterate over nf_tables_expressions list in __nft_expr_type_get(), and use rcu_read_lock() in the caller nft_expr_type_get() to protect the entire type query process.

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: total).
  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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