CyberSecBulletin
CVE-2025-38052NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2025-38052 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 d42ed4de6aba232d946d20653a70f79158a6535b, f5c2c4eaaa5a8e7e0685ec031d480e588e263e59, b8fcae6d2e93c54cacb8f579a77d827c1c643eb5 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 0.58% 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 d42ed4de6aba232d946d20653a70f79158a6535b or f5c2c4eaaa5a8e7e0685ec031d480e588e263e59 or b8fcae6d2e93c54cacb8f579a77d827c1c643eb5 or b19fc1d0be3c3397e5968fe2627f22e7f84673b1, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.238 or 5.15.185 or 6.1.141 or 6.6.93, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxfc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, d42ed4de6aba232d946d20653a70f79158a6535b; fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, f5c2c4eaaa5a8e7e0685ec031d480e588e263e59; fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, b8fcae6d2e93c54cacb8f579a77d827c1c643eb5; fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, b19fc1d0be3c3397e5968fe2627f22e7f84673b1; fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, 689a205cd968a1572ab561b0c4c2d50a10e9d3b0; fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, 4a0fddc2c0d5c28aec8c262ad4603be0bef1938c; fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 up to, but not including, e279024617134c94fd3e37470156534d5f2b3472; 5.5d42ed4de6aba232d946d20653a70f79158a6535b, f5c2c4eaaa5a8e7e0685ec031d480e588e263e59, b8fcae6d2e93c54cacb8f579a77d827c1c643eb5, b19fc1d0be3c3397e5968fe2627f22e7f84673b1, 689a205cd968a1572ab561b0c4c2d50a10e9d3b0, 4a0fddc2c0d5c28aec8c262ad4603be0bef1938c
LinuxLinux Kernel5.5 up to, but not including, 5.10.238; 5.11 up to, but not including, 5.15.185; 5.16 up to, but not including, 6.1.141; 6.2 up to, but not including, 6.6.93; 6.7 up to, but not including, 6.12.31; 6.13 up to, but not including, 6.14.9; 6.155.10.238, 5.15.185, 6.1.141, 6.6.93, 6.12.31, 6.14.9
DebianDebian Linux11.0Not stated

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.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: net/tipc: fix slab-use-after-free Read in tipc_aead_encrypt_done Syzbot reported a slab-use-after-free with the following call trace: ================================================================== BUG: KASAN: slab-use-after-free in tipc_aead_encrypt_done+0x4bd/0x510 net/tipc/crypto.c:840 Read of size 8 at addr ffff88807a733000 by task kworker/1:0/25 Call Trace: kasan_report+0xd9/0x110 mm/kasan/report.c:601 tipc_aead_encrypt_done+0x4bd/0x510 net/tipc/crypto.c:840 crypto_request_complete include/crypto/algapi.h:266 aead_request_complete include/crypto/internal/aead.h:85 cryptd_aead_crypt+0x3b8/0x750 crypto/cryptd.c:772 crypto_request_complete include/crypto/algapi.h:266 cryptd_queue_worker+0x131/0x200 crypto/cryptd.c:181 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231 Allocated by task 8355: kzalloc_noprof include/linux/slab.h:778 tipc_crypto_start+0xcc/0x9e0 net/tipc/crypto.c:1466 tipc_init_net+0x2dd/0x430 net/tipc/core.c:72 ops_init+0xb9/0x650 net/core/net_namespace.c:139 setup_net+0x435/0xb40 net/core/net_namespace.c:343 copy_net_ns+0x2f0/0x670 net/core/net_namespace.c:508 create_new_namespaces+0x3ea/0xb10 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228 ksys_unshare+0x419/0x970 kernel/fork.c:3323 __do_sys_unshare kernel/fork.c:3394 Freed by task 63: kfree+0x12a/0x3b0 mm/slub.c:4557 tipc_crypto_stop+0x23c/0x500 net/tipc/crypto.c:1539 tipc_exit_net+0x8c/0x110 net/tipc/core.c:119 ops_exit_list+0xb0/0x180 net/core/net_namespace.c:173 cleanup_net+0x5b7/0xbf0 net/core/net_namespace.c:640 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231 After freed the tipc_crypto tx by delete namespace, tipc_aead_encrypt_done may still visit it in cryptd_queue_worker workqueue. I reproduce this issue by: ip netns add ns1 ip link add veth1 type veth peer name veth2 ip link set veth1 netns ns1 ip netns exec ns1 tipc bearer enable media eth dev veth1 ip netns exec ns1 tipc node set key this_is_a_master_key master ip netns exec ns1 tipc bearer disable media eth dev veth1 ip netns del ns1 The key of reproduction is that, simd_aead_encrypt is interrupted, leading to crypto_simd_usable() return false. Thus, the cryptd_queue_worker is triggered, and the tipc_crypto tx will be visited. tipc_disc_timeout tipc_bearer_xmit_skb tipc_crypto_xmit tipc_aead_encrypt crypto_aead_encrypt // encrypt() simd_aead_encrypt // crypto_simd_usable() is false child = &ctx->cryptd_tfm->base; simd_aead_encrypt crypto_aead_encrypt // encrypt() cryptd_aead_encrypt_enqueue cryptd_aead_enqueue cryptd_enqueue_request // trigger cryptd_queue_worker queue_work_on(smp_processor_id(), cryptd_wq, &cpu_queue->work) Fix this by holding net reference count before encrypt.

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

References

Recent Use After Free vulnerabilities

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