CVE-2025-21727

HIGH EPSS 9.4%
Published Feb 27, 20251y ago · Modified Jun 17, 20262w ago
7.8 CVSS 3.1
High
Find Similar
Published Feb 27, 2025 1y ago
Last Modified Jun 17, 2026 2w ago

Description

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 Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
9.4% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-416 Use After Free Memory Safety

Affected Products 6

VendorProductVersionRange
linuxlinux_kernel*≥5.4  –  <5.10.235
linuxlinux_kernel*≥5.11  –  <5.15.179
linuxlinux_kernel*≥5.16  –  <6.1.129
linuxlinux_kernel*≥6.2  –  <6.6.76
linuxlinux_kernel*≥6.7  –  <6.12.13
linuxlinux_kernel*≥6.13  –  <6.13.2

References 10

  • cert-portal.siemens.com https://cert-portal.siemens.com/productcert/html/ssa-265688.html
  • git.kernel.org https://git.kernel.org/stable/c/0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/573ac9c70bf7885dc85d82fa44550581bfc3b738
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/80231f069240d52e98b6a317456c67b2eafd0781
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e01780ea4661172734118d2a5f41bc9720765668
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f3e0b9f790f8e8065d59e67b565a83154d9f3079
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f78170bee51469734b1a306a74fc5f777bb22ba6
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/573ac9c70bf7885dc85d82fa44550581bfc3b738
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/80231f069240d52e98b6a317456c67b2eafd0781
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e01780ea4661172734118d2a5f41bc9720765668
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f3e0b9f790f8e8065d59e67b565a83154d9f3079
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f78170bee51469734b1a306a74fc5f777bb22ba6
    Patch