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

AI Predicted 7.8 Difficulty: Moderate EPSS 0.01% · P3

Affected Version Matrix 23

VendorProductVersion RangeStatus
LinuxLinux714ba10a6dd19752a349e59aa875f3288ccb59b9< f77618291836168eca99e89cd175256f928f5e64affected
62f29ca45f832e281fc14966ac25f6ff3bd121ca< 4b49d939b5a79117f939b77cc67efae2694d9799affected
e4f2a1feebb3f209a0fca82aa53507a5b8be4d53< a7c41830ffcd17b2177a95a9b99b270302090c35affected
b07d5cc93e1b28df47a72c519d09d0a836043613< 64455c8051c3aedc71abb7ec8d47c80301f99f00affected
b07d5cc93e1b28df47a72c519d09d0a836043613< 3594aad97e7be2557ca9fa9c931b206b604028c8affected
b07d5cc93e1b28df47a72c519d09d0a836043613< 60b4b5c1277fc491da9e1e7abab307bfa39c2db7affected
b07d5cc93e1b28df47a72c519d09d0a836043613< c84e125fff2615b4d9c259e762596134eddd2f27affected
33ab4dd6202f359558a0a2678b94d1b9994c17e5affected
… +15 more rows
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I. Basic Information for CVE-2025-21887

Vulnerability Information
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Vulnerability Title
ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up
Source: NVD (National Vulnerability Database)
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>
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ovl过早释放upper dentry，可能导致释放后使用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
LinuxLinux 714ba10a6dd19752a349e59aa875f3288ccb59b9 ~ f77618291836168eca99e89cd175256f928f5e64 -
LinuxLinux 6.5 -

II. Public POCs for CVE-2025-21887

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III. Intelligence Information for CVE-2025-21887

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Patches & Fixes for CVE-2025-21887 (6)

Same Patch Batch · Linux · 2025-03-27 · 124 CVEs total

CVE-2023-52982fscache: Use wait_on_bit() to wait for the freeing of relinquished volume
CVE-2023-52998net: fec: Use page_pool_put_full_page when freeing rx buffers
CVE-2023-52999net: fix UaF in netns ops registration error path
CVE-2023-52997ipv4: prevent potential spectre v1 gadget in ip_metrics_convert()
CVE-2023-52996ipv4: prevent potential spectre v1 gadget in fib_metrics_match()
CVE-2023-52995riscv/kprobe: Fix instruction simulation of JALR
CVE-2023-52994acpi: Fix suspend with Xen PV
CVE-2023-52993x86/i8259: Mark legacy PIC interrupts with IRQ_LEVEL
CVE-2023-52992bpf: Skip task with pid=1 in send_signal_common()
CVE-2023-52991net: fix NULL pointer in skb_segment_list
CVE-2023-52989firewire: fix memory leak for payload of request subaction to IEC 61883-1 FCP region
CVE-2023-52988ALSA: hda/via: Avoid potential array out-of-bound in add_secret_dac_path()
CVE-2023-52987ASoC: SOF: ipc4-mtrace: prevent underflow in sof_ipc4_priority_mask_dfs_write()
CVE-2023-52986bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener
CVE-2023-52985arm64: dts: imx8mm-verdin: Do not power down eth-phy
CVE-2023-52984net: phy: dp83822: Fix null pointer access on DP83825/DP83826 devices
CVE-2023-52973vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF
CVE-2022-49761btrfs: always report error in run_one_delayed_ref()
CVE-2022-49760mm/hugetlb: fix PTE marker handling in hugetlb_change_protection()
CVE-2023-52974scsi: iscsi_tcp: Fix UAF during login when accessing the shost ipaddress

Showing top 20 of 124 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2025-21887

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