Executive Summary

Informations
Name CVE-2025-21796 First vendor Publication 2025-02-27
Vendor Cve Last vendor Modification 2025-03-21

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
 
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score N/A Attack Range N/A
Cvss Impact Score N/A Attack Complexity N/A
Cvss Expoit Score N/A Authentication N/A
Calculate full CVSS 2.0 Vectors scores

Detail

In the Linux kernel, the following vulnerability has been resolved:

nfsd: clear acl_access/acl_default after releasing them

If getting acl_default fails, acl_access and acl_default will be released simultaneously. However, acl_access will still retain a pointer pointing to the released posix_acl, which will trigger a WARNING in nfs3svc_release_getacl like this:

------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 26 PID: 3199 at lib/refcount.c:28 refcount_warn_saturate+0xb5/0x170 Modules linked in: CPU: 26 UID: 0 PID: 3199 Comm: nfsd Not tainted 6.12.0-rc6-00079-g04ae226af01f-dirty #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:refcount_warn_saturate+0xb5/0x170 Code: cc cc 0f b6 1d b3 20 a5 03 80 fb 01 0f 87 65 48 d8 00 83 e3 01 75 e4 48 c7 c7 c0 3b 9b 85 c6 05 97 20 a5 03 01 e8 fb 3e 30 ff <0f> 0b eb cd 0f b6 1d 8a3 RSP: 0018:ffffc90008637cd8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83904fde RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88871ed36380 RBP: ffff888158beeb40 R08: 0000000000000001 R09: fffff520010c6f56 R10: ffffc90008637ab7 R11: 0000000000000001 R12: 0000000000000001 R13: ffff888140e77400 R14: ffff888140e77408 R15: ffffffff858b42c0 FS: 0000000000000000(0000) GS:ffff88871ed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562384d32158 CR3: 000000055cc6a000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace:

? refcount_warn_saturate+0xb5/0x170
? __warn+0xa5/0x140
? refcount_warn_saturate+0xb5/0x170
? report_bug+0x1b1/0x1e0
? handle_bug+0x53/0xa0
? exc_invalid_op+0x17/0x40
? asm_exc_invalid_op+0x1a/0x20
? tick_nohz_tick_stopped+0x1e/0x40
? refcount_warn_saturate+0xb5/0x170
? refcount_warn_saturate+0xb5/0x170
nfs3svc_release_getacl+0xc9/0xe0
svc_process_common+0x5db/0xb60
? __pfx_svc_process_common+0x10/0x10
? __rcu_read_unlock+0x69/0xa0
? __pfx_nfsd_dispatch+0x10/0x10
? svc_xprt_received+0xa1/0x120
? xdr_init_decode+0x11d/0x190
svc_process+0x2a7/0x330
svc_handle_xprt+0x69d/0x940
svc_recv+0x180/0x2d0
nfsd+0x168/0x200
? __pfx_nfsd+0x10/0x10
kthread+0x1a2/0x1e0
? kthread+0xf4/0x1e0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x60
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
Kernel panic - not syncing: kernel: panic_on_warn set ...

Clear acl_access/acl_default after posix_acl_release is called to prevent UAF from being triggered.

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21796

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 8
Os 3713

Sources (Detail)

https://git.kernel.org/stable/c/1fd94884174bd20beb1773990fd3b1aa877688d9
https://git.kernel.org/stable/c/2e59b2b68782519560b3d6a41dd66a3d01a01cd3
https://git.kernel.org/stable/c/55d947315fb5f67a35e4e1d3e01bb886b9c6decf
https://git.kernel.org/stable/c/6f7cfee1a316891890c505563aa54f3476db52fd
https://git.kernel.org/stable/c/7faf14a7b0366f153284db0ad3347c457ea70136
https://git.kernel.org/stable/c/8a1737ae42c928384ab6447f6ee1a882510e85fa
https://git.kernel.org/stable/c/f8d871523142f7895f250a856f8c4a4181614510
Source Url

Alert History

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Date Informations
2025-06-26 02:41:01
  • Multiple Updates
2025-06-25 12:38:04
  • Multiple Updates
2025-06-24 02:45:27
  • Multiple Updates
2025-05-27 02:52:29
  • Multiple Updates
2025-03-28 17:20:52
  • Multiple Updates
2025-03-28 13:49:04
  • Multiple Updates
2025-03-28 03:24:24
  • Multiple Updates
2025-03-25 03:30:13
  • Multiple Updates
2025-03-21 17:20:41
  • Multiple Updates
2025-03-13 17:20:42
  • Multiple Updates
2025-02-28 03:46:08
  • Multiple Updates
2025-02-28 03:46:04
  • Multiple Updates
2025-02-27 21:20:33
  • Multiple Updates
2025-02-27 09:20:31
  • First insertion