CVE-2025-21887 - CVE House
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Status published Unknown CVE-2025-21887

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

Vulnerability Description

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>

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

Linux
Vulnerable Versions:
714ba10a6dd19752a349e59aa875f3288ccb59b9, 62f29ca45f832e281fc14966ac25f6ff3bd121ca, e4f2a1feebb3f209a0fca82aa53507a5b8be4d53, b07d5cc93e1b28df47a72c519d09d0a836043613, 33ab4dd6202f359558a0a2678b94d1b9994c17e5, 1ecdc55e5cd9f70f8d7513802971d4cffb9f77af, 5.10.188, 5.15.121, 6.1.39, 6.3.13, 6.4.4, 6.5, 0, 5.10.247, 5.15.179, 6.1.130, 6.6.81, 6.12.18, 6.13.6, 6.14

Timeline

Official Publish: March 27th, 2025
Last Modified: July 14th, 2026
Added to House: July 22nd, 2026

CVSS Vectors

No vector data available

Weaknesses (CWE)

No CWE data available

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.