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CVE-2026-53070NVD status: Modified

Linux: Concurrent Execution using Shared Resource with Improper Synchronization

Published Updated By the CyberSecBulletin desk

CVE-2026-53070 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions e2933f5b3a31b175628985b92895269b778674a1, 7f0062c40781fe0a340965f5bb0816681982ff4c, be3bfcb34bda04f6a350710db471d4133f950f2c 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 0.3% 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 e2933f5b3a31b175628985b92895269b778674a1 or 7f0062c40781fe0a340965f5bb0816681982ff4c or be3bfcb34bda04f6a350710db471d4133f950f2c or 0de7db2eb27e82b983157016fa604b1ba664ae5f, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.12.95 or 6.18.37 or 7.0.10, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux046c052b475e7119b6a30e3483e2888fc606a2f8 up to, but not including, e2933f5b3a31b175628985b92895269b778674a1; 046c052b475e7119b6a30e3483e2888fc606a2f8 up to, but not including, 7f0062c40781fe0a340965f5bb0816681982ff4c; 046c052b475e7119b6a30e3483e2888fc606a2f8 up to, but not including, be3bfcb34bda04f6a350710db471d4133f950f2c; 046c052b475e7119b6a30e3483e2888fc606a2f8 up to, but not including, 0de7db2eb27e82b983157016fa604b1ba664ae5f; 046c052b475e7119b6a30e3483e2888fc606a2f8 up to, but not including, 790093245e35040c2adb15f48970020425aa3f47; 046c052b475e7119b6a30e3483e2888fc606a2f8 up to, but not including, 2cd7e6971fc2787408ceef17906ea152791448cf; 5.11e2933f5b3a31b175628985b92895269b778674a1, 7f0062c40781fe0a340965f5bb0816681982ff4c, be3bfcb34bda04f6a350710db471d4133f950f2c, 0de7db2eb27e82b983157016fa604b1ba664ae5f, 790093245e35040c2adb15f48970020425aa3f47, 2cd7e6971fc2787408ceef17906ea152791448cf
LinuxLinux Kernel5.11 up to, but not including, 6.12.95; 6.13 up to, but not including, 6.18.37; 6.19 up to, but not including, 7.0.106.12.95, 6.18.37, 7.0.10

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: disable BH before calling udp_tunnel_xmit_skb() udp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with BH disabled. After commit 6f1a9140ecda ("add xmit recursion limit to tunnel xmit functions"), on the path: udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit() dev_xmit_recursion_inc()/dec() must stay balanced on the same CPU. Without local_bh_disable(), the context may move between CPUs, which can break the inc/dec pairing. This may lead to incorrect recursion level detection and cause packets to be dropped in ip(6)_tunnel_xmit() or __dev_queue_xmit(). Fix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths. In my testing, after enabling the SCTP over UDP: # ip net exec ha sysctl -w net.sctp.udp_port=9899 # ip net exec ha sysctl -w net.sctp.encap_port=9899 # ip net exec hb sysctl -w net.sctp.udp_port=9899 # ip net exec hb sysctl -w net.sctp.encap_port=9899 # ip net exec ha iperf3 -s - without this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 37.2 MBytes 31.2 Mbits/sec sender [ 5] 0.00-10.00 sec 37.1 MBytes 31.1 Mbits/sec receiver - with this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec sender [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec receiver

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: yes, 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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