CVE-2025-21887

ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track*

*SSVC

Descriptions

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>

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>

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Complete

Integrity

None

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:Track*

Exploitation

None

Automatable

Tech. Impact

Total

* Organization's Worst-case Scenario

Timeline

2024-12-29 CVE Reserved
2025-03-27 CVE Published
2025-03-27 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-416: Use After Free

CAPEC

References (12)

URL	Tag	Source
https://git.kernel.org/stable/c/62f29ca45f832e281fc14966ac25f6ff3bd121ca	Vuln. Introduced
https://git.kernel.org/stable/c/e4f2a1feebb3f209a0fca82aa53507a5b8be4d53	Vuln. Introduced
https://git.kernel.org/stable/c/b07d5cc93e1b28df47a72c519d09d0a836043613	Vuln. Introduced
https://git.kernel.org/stable/c/714ba10a6dd19752a349e59aa875f3288ccb59b9	Vuln. Introduced
https://git.kernel.org/stable/c/33ab4dd6202f359558a0a2678b94d1b9994c17e5	Vuln. Introduced
https://git.kernel.org/stable/c/1ecdc55e5cd9f70f8d7513802971d4cffb9f77af	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/4b49d939b5a79117f939b77cc67efae2694d9799	2025-03-13
https://git.kernel.org/stable/c/a7c41830ffcd17b2177a95a9b99b270302090c35	2025-03-07
https://git.kernel.org/stable/c/64455c8051c3aedc71abb7ec8d47c80301f99f00	2025-03-07
https://git.kernel.org/stable/c/3594aad97e7be2557ca9fa9c931b206b604028c8	2025-03-07
https://git.kernel.org/stable/c/60b4b5c1277fc491da9e1e7abab307bfa39c2db7	2025-03-07
https://git.kernel.org/stable/c/c84e125fff2615b4d9c259e762596134eddd2f27	2025-02-19

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.15.121 < 5.15.179 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15.121 < 5.15.179"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 6.1.39 < 6.1.130 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.1.39 < 6.1.130"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 6.5 < 6.6.81 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.5 < 6.6.81"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 6.5 < 6.12.18 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.5 < 6.12.18"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 6.5 < 6.13.6 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.5 < 6.13.6"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 6.5 < 6.14 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.5 < 6.14"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				5.10.188 Search vendor "Linux" for product "Linux Kernel" and version "5.10.188"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				6.3.13 Search vendor "Linux" for product "Linux Kernel" and version "6.3.13"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				6.4.4 Search vendor "Linux" for product "Linux Kernel" and version "6.4.4"		en		Affected