High 7.8Published Feb 26, 2025

CVE-2025-21727padata: fix UAF in padata_reorder

Updated under an hour ago (Oct 28, 2026, 8:30 AM ET)

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Exploited in the last 30 days

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/20221028160401.cccypv4euxikusiq@parnassus.localdomain/ [2] https://lore.kernel.org/linux-kernel/jfjz5d7zwbytztackem7ibzalm5lnxldi2eofeiczqmqs2m7o6@fq426cwnjtkm/

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from b128a30409356df65f1a51cff3eb986cac8cfedc before f78170bee51469734b1a306a74fc5f777bb22ba6; from b128a30409356df65f1a51cff3eb986cac8cfedc before f3e0b9f790f8e8065d59e67b565a83154d9f3079; from b128a30409356df65f1a51cff3eb986cac8cfedc before 0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd; from b128a30409356df65f1a51cff3eb986cac8cfedc before bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de; from b128a30409356df65f1a51cff3eb986cac8cfedc before 573ac9c70bf7885dc85d82fa44550581bfc3b738; from b128a30409356df65f1a51cff3eb986cac8cfedc before 80231f069240d52e98b6a317456c67b2eafd0781; from b128a30409356df65f1a51cff3eb986cac8cfedc before e01780ea4661172734118d2a5f41bc9720765668	CNA record
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 5.4 before 5.10.235; from 5.11 before 5.15.179; from 5.16 before 6.1.129; from 6.2 before 6.6.76; from 6.7 before 6.12.13; from 6.13 before 6.13.2	NVD

References

References

https://git.kernel.org/stable/c/f78170bee51469734b1a306a74fc5f777bb22ba6	patch
https://git.kernel.org/stable/c/f3e0b9f790f8e8065d59e67b565a83154d9f3079	patch
https://git.kernel.org/stable/c/0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd	patch
https://git.kernel.org/stable/c/bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de	patch
https://git.kernel.org/stable/c/573ac9c70bf7885dc85d82fa44550581bfc3b738	patch
https://git.kernel.org/stable/c/80231f069240d52e98b6a317456c67b2eafd0781	patch
https://git.kernel.org/stable/c/e01780ea4661172734118d2a5f41bc9720765668	patch
https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
https://cert-portal.siemens.com/productcert/html/ssa-265688.html
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.