CyberSecBulletin
CVE-2026-64352NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64352 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 f0967d4f1ba4323a3cb7dc8fdba74dd3a8caaf04, 304ca50582f0c047370f85e13caec456f78c9fcc, ec662a8b2cde01e76b37ccd4b992d0342299e69c 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 f0967d4f1ba4323a3cb7dc8fdba74dd3a8caaf04 or 304ca50582f0c047370f85e13caec456f78c9fcc or ec662a8b2cde01e76b37ccd4b992d0342299e69c or 9bfdf4b81b0e56d47bc6c46c34a46638be716695, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.15.212 or 6.1.178 or 6.6.145 or 6.12.97, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux694cea395fded425008e93cd90cfdf7a451674af up to, but not including, f0967d4f1ba4323a3cb7dc8fdba74dd3a8caaf04; 694cea395fded425008e93cd90cfdf7a451674af up to, but not including, 304ca50582f0c047370f85e13caec456f78c9fcc; 694cea395fded425008e93cd90cfdf7a451674af up to, but not including, ec662a8b2cde01e76b37ccd4b992d0342299e69c; 694cea395fded425008e93cd90cfdf7a451674af up to, but not including, 9bfdf4b81b0e56d47bc6c46c34a46638be716695; 694cea395fded425008e93cd90cfdf7a451674af up to, but not including, 57454944737f3ad9a8703aecbbb79713b513a94b; 694cea395fded425008e93cd90cfdf7a451674af up to, but not including, bd6ad9a6b30498d845413e863fb95c6fab3babe3; 694cea395fded425008e93cd90cfdf7a451674af up to, but not including, 2f884d371fafea137afea504d49ee4a7c8d7985b; 5.14f0967d4f1ba4323a3cb7dc8fdba74dd3a8caaf04, 304ca50582f0c047370f85e13caec456f78c9fcc, ec662a8b2cde01e76b37ccd4b992d0342299e69c, 9bfdf4b81b0e56d47bc6c46c34a46638be716695, 57454944737f3ad9a8703aecbbb79713b513a94b, bd6ad9a6b30498d845413e863fb95c6fab3babe3
LinuxLinux Kernel5.14 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, 6.12.97; 6.13 up to, but not including, 6.18.40; 6.19 up to, but not including, 7.1.45.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.4

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.

Official description

In the Linux kernel, the following vulnerability has been resolved: bpf: Allow LPM map access from sleepable BPF programs trie_lookup_elem() annotates its rcu_dereference_check() walks with only rcu_read_lock_bh_held(). Because rcu_dereference_check(p, c) resolves to "c || rcu_read_lock_held()", this passes for XDP/NAPI and classic RCU readers but fails for sleepable BPF programs, which enter via __bpf_prog_enter_sleepable() and hold only rcu_read_lock_trace(). trie_update_elem() and trie_delete_elem() have the same problem in a different form: they walk the trie with plain rcu_dereference(), which asserts rcu_read_lock_held() unconditionally. Both are reachable from sleepable BPF programs via the bpf_map_update_elem / bpf_map_delete_elem helpers, and from the syscall path under classic rcu_read_lock(). In the writer paths the trie is actually protected by trie->lock (an rqspinlock taken across the walk); we never relied on the RCU read-side lock to keep nodes alive there. A sleepable LSM hook that ends up touching an LPM trie therefore triggers lockdep on debug kernels: ============================= WARNING: suspicious RCU usage 7.1.0-... Tainted: G E ----------------------------- kernel/bpf/lpm_trie.c:249 suspicious rcu_dereference_check() usage! 1 lock held by net_tests/540: #0: (rcu_tasks_trace_srcu_struct){....}-{0:0}, at: __bpf_prog_enter_sleepable+0x26/0x280 Call Trace: dump_stack_lvl lockdep_rcu_suspicious trie_lookup_elem bpf_prog_..._enforce_security_socket_connect bpf_trampoline_... security_socket_connect __sys_connect do_syscall_64 This is lockdep-only -- no UAF, since Tasks Trace RCU does serialize against the trie's reclaim path -- but it spams the console once per distinct callsite on every debug kernel running a sleepable BPF LSM that touches an LPM trie, which is increasingly common. For the lookup path, switch the rcu_dereference_check() annotation from rcu_read_lock_bh_held() to bpf_rcu_lock_held(), which accepts all three contexts (classic, BH, Tasks Trace). Other map types already follow this convention. For trie_update_elem() and trie_delete_elem(), annotate the walks as rcu_dereference_protected(*p, 1) -- matching trie_free() in the same file -- since trie->lock is held across the walk. rqspinlock has no lockdep_map, so the predicate degenerates to '1' rather than lockdep_is_held(&trie->lock); the protection is real but not machine-verifiable. trie_get_next_key() also uses bare rcu_dereference() but is reachable only from the BPF syscall, which holds classic rcu_read_lock() before dispatching, so it is left untouched.

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: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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