CyberSecBulletin
CVE-2026-64189NVD status: Modified

Linux: Concurrent Execution using Shared Resource with Improper Synchronization

Published Updated By the CyberSecBulletin desk

CVE-2026-64189 is a high-severity concurrent execution using shared resource with improper synchronization 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 a7a299277959683204d73333c32c092fd69327d4, 1bc67c3fc98e9fc07032cc56afcdbc690c47d11e, e8a9976b61f1bc4aa7fd25fa26726dfdf2adf710 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 0.13% 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 a7a299277959683204d73333c32c092fd69327d4 or 1bc67c3fc98e9fc07032cc56afcdbc690c47d11e or e8a9976b61f1bc4aa7fd25fa26726dfdf2adf710 or 96fbafc20ebd9a613736c2998b89c539fe3042f5, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.20 or 5.10.261 or 5.15.212 or 6.1.178, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, a7a299277959683204d73333c32c092fd69327d4; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, 1bc67c3fc98e9fc07032cc56afcdbc690c47d11e; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, e8a9976b61f1bc4aa7fd25fa26726dfdf2adf710; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, 96fbafc20ebd9a613736c2998b89c539fe3042f5; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, ff86ea9b7fdf70564e60436fbee68c96bc459943; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, 81d54c766337b923eec26da0a13406760b091093; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, e8ee198bbc04a32d336e79160fde980e0235b39f; 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 up to, but not including, 7cd9103283b26b917360ec99d7d2f2d761bcf1ab; and 3 more rangesa7a299277959683204d73333c32c092fd69327d4, 1bc67c3fc98e9fc07032cc56afcdbc690c47d11e, e8a9976b61f1bc4aa7fd25fa26726dfdf2adf710, 96fbafc20ebd9a613736c2998b89c539fe3042f5, ff86ea9b7fdf70564e60436fbee68c96bc459943, 81d54c766337b923eec26da0a13406760b091093
LinuxLinux Kernel4.19.5 up to, but not including, 4.20; 4.20.1 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4; and 2 more ranges4.20, 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96

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 CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: fix race between dump and ip_set_list resize The release path of ip_set_dump_do() and ip_set_dump_done() read inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw() of the array pointer. These run from netlink_recvmsg() without the nfnl mutex and without an RCU read-side critical section. A concurrent ip_set_create() can grow the array: it publishes the new array, calls synchronize_net() and then kvfree()s the old one. Since the dump paths read the array outside any RCU reader, synchronize_net() does not wait for them and the old array can be freed while they still index into it, causing a use-after-free. The dumped set itself stays pinned via set->ref_netlink, so only the array load needs protecting. Take rcu_read_lock() around it, matching ip_set_get_byname() and __ip_set_put_byindex(). BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697) Read of size 8 at addr ffff88800b5c4018 by task exploit/150 Call Trace: ... kasan_report (mm/kasan/report.c:595) ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697) netlink_dump (net/netlink/af_netlink.c:2325) netlink_recvmsg (net/netlink/af_netlink.c:1976) sock_recvmsg (net/socket.c:1159) __sys_recvfrom (net/socket.c:2315) ... Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7] RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698) Kernel panic - not syncing: Fatal exception

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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