UBUNTU-CVE-2025-21727
In the Linux kernel, the following vulnerability has been resolved: padata: fix UAF in padata_reorder A bug was found when run ltp test: BUG: KASAN: slab-use-after-free in padata_find_next+0x29/0x1a0 Read of size 4 at addr ffff88bbfe003524 by task kworker/u113:2/3039206 CPU: 0 PID: 3039206 Comm: kworker/u113:2 Kdump: loaded Not tainted 6.6.0+ Workqueue: pdecrypt_parallel padata_parallel_worker Call Trace: <TASK> dump_stack_lvl+0x32/0x50 print_address_description.constprop.0+0x6b/0x3d0 print_report+0xdd/0x2c0 kasan_report+0xa5/0xd0 padata_find_next+0x29/0x1a0 padata_reorder+0x131/0x220 padata_parallel_worker+0x3d/0xc0 process_one_work+0x2ec/0x5a0 If 'mdelay(10)' is added before calling 'padata_find_next' in the 'padata_reorder' function, this issue could be reproduced easily with ltp test (pcrypt_aead01). This can be explained as bellow: pcrypt_aead_encrypt ... padata_do_parallel refcount_inc(&pd->refcnt); // add refcnt ... padata_do_serial padata_reorder // pd while (1) { padata_find_next(pd, true); // using pd queue_work_on ... padata_serial_worker crypto_del_alg padata_put_pd_cnt // sub refcnt padata_free_shell padata_put_pd(ps->pd); // pd is freed // loop again, but pd is freed // call padata_find_next, UAF } In the padata_reorder function, when it loops in 'while', if the alg is deleted, the refcnt may be decreased to 0 before entering 'padata_find_next', which leads to UAF. As mentioned in [1], do_serial is supposed to be called with BHs disabled and always happen under RCU protection, to address this issue, add synchronize_rcu() in 'padata_free_shell' wait for all _do_serial calls to finish. [1] https://lore.kernel.org/all/[email protected]/ [2] https://lore.kernel.org/linux-kernel/jfjz5d7zwbytztackem7ibzalm5lnxldi2eofeiczqmqs2m7o6@fq426cwnjtkm/
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
44 explicit affected versions
108 explicit affected versions
45 explicit affected versions
63 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
73 explicit affected versions
24 explicit affected versions
58 explicit affected versions
82 explicit affected versions
66 explicit affected versions
59 explicit affected versions
10 explicit affected versions
17 explicit affected versions
24 explicit affected versions
65 explicit affected versions
7 explicit affected versions
64 explicit affected versions
21 explicit affected versions
13 explicit affected versions
23 explicit affected versions
35 explicit affected versions
25 explicit affected versions
23 explicit affected versions
18 explicit affected versions
24 explicit affected versions
64 explicit affected versions
26 explicit affected versions
112 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
31 explicit affected versions
115 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
66 explicit affected versions
27 explicit affected versions
5 explicit affected versions
7 explicit affected versions
12 explicit affected versions
4 explicit affected versions
56 explicit affected versions
12 explicit affected versions
14 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
97 explicit affected versions
12 explicit affected versions
98 explicit affected versions
12 explicit affected versions
21 explicit affected versions
19 explicit affected versions
18 explicit affected versions
13 explicit affected versions
10 explicit affected versions
37 explicit affected versions
5 explicit affected versions
13 explicit affected versions
19 explicit affected versions
10 explicit affected versions
40 explicit affected versions
1 explicit affected versions
26 explicit affected versions
13 explicit affected versions
14 explicit affected versions
29 explicit affected versions
102 explicit affected versions
13 explicit affected versions
70 explicit affected versions
20 explicit affected versions
21 explicit affected versions
93 explicit affected versions
65 explicit affected versions
28 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
1 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
56 explicit affected versions
50 explicit affected versions
66 explicit affected versions
10 explicit affected versions
26 explicit affected versions
25 explicit affected versions
1 explicit affected versions
14 explicit affected versions
26 explicit affected versions
13 explicit affected versions
26 explicit affected versions
70 explicit affected versions
16 explicit affected versions
67 explicit affected versions
29 explicit affected versions
54 explicit affected versions
3 explicit affected versions
123 explicit affected versions
1 explicit affected versions
4 explicit affected versions
2 explicit affected versions
51 explicit affected versions
13 explicit affected versions
23 explicit affected versions
12 explicit affected versions
53 explicit affected versions
27 explicit affected versions
40 explicit affected versions
112 explicit affected versions
1 explicit affected versions
22 explicit affected versions
8 explicit affected versions
30 explicit affected versions
5 explicit affected versions
8 explicit affected versions
1 explicit affected versions
10 explicit affected versions
4 explicit affected versions
25 explicit affected versions
13 explicit affected versions
101 explicit affected versions
13 explicit affected versions
64 explicit affected versions
7 explicit affected versions
3 explicit affected versions
57 explicit affected versions
10 explicit affected versions
12 explicit affected versions
15 explicit affected versions
100 explicit affected versions
73 explicit affected versions
47 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
30 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
55 explicit affected versions
11 explicit affected versions
19 explicit affected versions
7 explicit affected versions
66 explicit affected versions
7 explicit affected versions
35 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
64 explicit affected versions
56 explicit affected versions
13 explicit affected versions
43 explicit affected versions
68 explicit affected versions
110 explicit affected versions
10 explicit affected versions
8 explicit affected versions
24 explicit affected versions
80 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
114 explicit affected versions
19 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: padata: fix UAF in padata_reorder A bug was found when run ltp test: BUG: KASAN: slab-use-after-free in padata_find_next+0x29/0x1a0 Read of size 4 at addr ffff88bbfe003524 by task kworker/u113:2/3039206 CPU: 0 PID: 3039206 Comm: kworker/u113:2 Kdump: loaded Not tainted 6.6.0+ Workqueue: pdecrypt_parallel padata_parallel_worker Call Trace: <TASK> dump_stack_lvl+0x32/0x50 print_address_description.constprop.0+0x6b/0x3d0 print_report+0xdd/0x2c0 kasan_report+0xa5/0xd0 padata_find_next+0x29/0x1a0 padata_reorder+0x131/0x220 padata_parallel_worker+0x3d/0xc0 process_one_work+0x2ec/0x5a0 If 'mdelay(10)' is added before calling 'padata_find_next' in the 'padata_reorder' function, this issue could be reproduced easily with ltp test (pcrypt_aead01). This can be explained as bellow: pcrypt_aead_encrypt ... padata_do_parallel refcount_inc(&pd->refcnt); // add refcnt ... padata_do_serial padata_reorder // pd while (1) { padata_find_next(pd, true); // using pd queue_work_on ... padata_serial_worker crypto_del_alg padata_put_pd_cnt // sub refcnt padata_free_shell padata_put_pd(ps->pd); // pd is freed // loop again, but pd is freed // call padata_find_next, UAF } In the padata_reorder function, when it loops in 'while', if the alg is deleted, the refcnt may be decreased to 0 before entering 'padata_find_next', which leads to UAF. As mentioned in [1], do_serial is supposed to be called with BHs disabled and always happen under RCU protection, to address this issue, add synchronize_rcu() in 'padata_free_shell' wait for all _do_serial calls to finish. [1] https://lore.kernel.org/all/[email protected]/ [2] https://lore.kernel.org/linux-kernel/jfjz5d7zwbytztackem7ibzalm5lnxldi2eofeiczqmqs2m7o6@fq426cwnjtkm/
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/e01780ea4661172734118d2a5f41bc9720765668
- https://git.kernel.org/stable/c/0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd
- https://git.kernel.org/stable/c/573ac9c70bf7885dc85d82fa44550581bfc3b738
- https://git.kernel.org/stable/c/80231f069240d52e98b6a317456c67b2eafd0781
- https://git.kernel.org/stable/c/bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de
- https://git.kernel.org/stable/c/e01780ea4661172734118d2a5f41bc9720765668
- https://ubuntu.com/security/CVE-2025-21727
- https://ubuntu.com/security/notices/USN-7510-1
- https://ubuntu.com/security/notices/USN-7510-2
- https://ubuntu.com/security/notices/USN-7510-3
- https://ubuntu.com/security/notices/USN-7510-4
- https://ubuntu.com/security/notices/USN-7510-5
- https://ubuntu.com/security/notices/USN-7510-6
- https://ubuntu.com/security/notices/USN-7510-7
- https://ubuntu.com/security/notices/USN-7510-8
- https://ubuntu.com/security/notices/USN-7511-1
- https://ubuntu.com/security/notices/USN-7511-2
- https://ubuntu.com/security/notices/USN-7511-3
- https://ubuntu.com/security/notices/USN-7512-1
- https://ubuntu.com/security/notices/USN-7521-1
- https://ubuntu.com/security/notices/USN-7521-2
- https://ubuntu.com/security/notices/USN-7521-3
- https://ubuntu.com/security/notices/USN-7593-1
- https://ubuntu.com/security/notices/USN-7602-1
- https://ubuntu.com/security/notices/USN-7651-1
- https://ubuntu.com/security/notices/USN-7651-2
- https://ubuntu.com/security/notices/USN-7651-3
- https://ubuntu.com/security/notices/USN-7651-4
- https://ubuntu.com/security/notices/USN-7651-5
- https://ubuntu.com/security/notices/USN-7651-6
- https://ubuntu.com/security/notices/USN-7652-1
- https://ubuntu.com/security/notices/USN-7653-1
- https://ubuntu.com/security/notices/USN-7737-1
- https://ubuntu.com/security/notices/USN-7874-1
- https://ubuntu.com/security/notices/USN-7874-2
- https://ubuntu.com/security/notices/USN-7874-3
- https://ubuntu.com/security/notices/USN-7939-1
- https://ubuntu.com/security/notices/USN-7939-2
- https://www.cve.org/CVERecord?id=CVE-2025-21727