High 7.8Published Mar 27, 2025

CVE-2025-21887ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up

Updated under an hour ago (2026-10-19 07:10 UTC)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up The issue was caused by dput(upper) being called before ovl_dentry_update_reval(), while upper->d_flags was still accessed in ovl_dentry_remote(). Move dput(upper) after its last use to prevent use-after-free. BUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline] BUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 ovl_dentry_remote fs/overlayfs/util.c:162 [inline] ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 ovl_link_up fs/overlayfs/copy_up.c:610 [inline] ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170 ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223 ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136 vfs_rename+0xf84/0x20a0 fs/namei.c:4893 ... </TASK>

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 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 714ba10a6dd19752a349e59aa875f3288ccb59b9 before f77618291836168eca99e89cd175256f928f5e64; 62f29ca45f832e281fc14966ac25f6ff3bd121ca builds before 4b49d939b5a79117f939b77cc67efae2694d9799; from e4f2a1feebb3f209a0fca82aa53507a5b8be4d53 before a7c41830ffcd17b2177a95a9b99b270302090c35; from b07d5cc93e1b28df47a72c519d09d0a836043613 before 64455c8051c3aedc71abb7ec8d47c80301f99f00; from b07d5cc93e1b28df47a72c519d09d0a836043613 before 3594aad97e7be2557ca9fa9c931b206b604028c8; from b07d5cc93e1b28df47a72c519d09d0a836043613 before 60b4b5c1277fc491da9e1e7abab307bfa39c2db7; from b07d5cc93e1b28df47a72c519d09d0a836043613 before c84e125fff2615b4d9c259e762596134eddd2f27; 33ab4dd6202f359558a0a2678b94d1b9994c17e5; and 6 more ranges	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 5.10.188 before 5.11; from 5.15.121 before 5.15.179; from 6.1.39 before 6.1.130; from 6.3.13 before 6.4; from 6.4.4 before 6.6.81; from 6.7 before 6.12.18; from 6.13 before 6.13.6; 6.14; and 3 more ranges	NVD

References

https://git.kernel.org/stable/c/f77618291836168eca99e89cd175256f928f5e64
https://git.kernel.org/stable/c/4b49d939b5a79117f939b77cc67efae2694d9799patch
https://git.kernel.org/stable/c/a7c41830ffcd17b2177a95a9b99b270302090c35patch
https://git.kernel.org/stable/c/64455c8051c3aedc71abb7ec8d47c80301f99f00patch
https://git.kernel.org/stable/c/3594aad97e7be2557ca9fa9c931b206b604028c8patch
https://git.kernel.org/stable/c/60b4b5c1277fc491da9e1e7abab307bfa39c2db7patch
https://git.kernel.org/stable/c/c84e125fff2615b4d9c259e762596134eddd2f27patch
https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html

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.