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CVE-2025-21796— nfsd: clear acl_access/acl_default after releasing them

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

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存在资源管理错误漏洞，该漏洞源于未正确清理acl_access和acl_default，可能导致释放后重用。

CVSS 9.8 · Critical EPSS 0.62% · P47

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux a257cdd0e2179630d3201c32ba14d7fcb3c3a055< 8a1737ae42c928384ab6447f6ee1a882510e85fa affected
a257cdd0e2179630d3201c32ba14d7fcb3c3a055< 6f7cfee1a316891890c505563aa54f3476db52fd affected
a257cdd0e2179630d3201c32ba14d7fcb3c3a055< 2e59b2b68782519560b3d6a41dd66a3d01a01cd3 affected
a257cdd0e2179630d3201c32ba14d7fcb3c3a055< 55d947315fb5f67a35e4e1d3e01bb886b9c6decf affected
a257cdd0e2179630d3201c32ba14d7fcb3c3a055< f8d871523142f7895f250a856f8c4a4181614510 affected
a257cdd0e2179630d3201c32ba14d7fcb3c3a055< 1fd94884174bd20beb1773990fd3b1aa877688d9 affected
a257cdd0e2179630d3201c32ba14d7fcb3c3a055< 7faf14a7b0366f153284db0ad3347c457ea70136 affected
2.6.13 affected
… +8 more rows
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I. Basic Information for CVE-2025-21796

Vulnerability Information
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Vulnerability Title
nfsd: clear acl_access/acl_default after releasing them
Source: CVE Program / CVE List V5
Vulnerability Description
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: <TASK> ? 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 </TASK> 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 资源管理错误漏洞
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存在资源管理错误漏洞，该漏洞源于未正确清理acl_access和acl_default，可能导致释放后重用。
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

Vendor Product Affected Versions CPE Subscribe
Linux Linux a257cdd0e2179630d3201c32ba14d7fcb3c3a055 ~ 8a1737ae42c928384ab6447f6ee1a882510e85fa -
Linux Linux 2.6.13 -

II. Public POCs for CVE-2025-21796

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III. Intelligence Information for CVE-2025-21796

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Patches & Fixes for CVE-2025-21796 (5)

Other References for CVE-2025-21796 (2)

Same Patch Batch · Linux · 2025-02-27 · 177 CVEs total

CVE-2025-21805 9.8 CRITICAL RDMA/rtrs: Add missing deinit() call
CVE-2025-21707 9.8 CRITICAL mptcp: consolidate suboption status
CVE-2025-21748 9.8 CRITICAL ksmbd: fix integer overflows on 32 bit systems
CVE-2024-58006 9.6 CRITICAL PCI: dwc: ep: Prevent changing BAR size/flags in pci_epc_set_bar()
CVE-2024-57999 8.8 HIGH powerpc/pseries/iommu: IOMMU incorrectly marks MMIO range in DDW
CVE-2025-21735 8.8 HIGH NFC: nci: Add bounds checking in nci_hci_create_pipe()
CVE-2024-57997 8.8 HIGH wifi: wcn36xx: fix channel survey memory allocation size
CVE-2024-57995 8.8 HIGH wifi: ath12k: fix read pointer after free in ath12k_mac_assign_vif_to_vdev()
CVE-2025-21710 8.2 HIGH tcp: correct handling of extreme memory squeeze
CVE-2025-21766 8.1 HIGH ipv4: use RCU protection in __ip_rt_update_pmtu()
CVE-2024-57973 8.1 HIGH rdma/cxgb4: Prevent potential integer overflow on 32bit
CVE-2025-21765 8.1 HIGH ipv6: use RCU protection in ip6_default_advmss()
CVE-2025-21762 8.1 HIGH arp: use RCU protection in arp_xmit()
CVE-2025-21760 8.1 HIGH ndisc: extend RCU protection in ndisc_send_skb()
CVE-2025-21764 7.8 HIGH ndisc: use RCU protection in ndisc_alloc_skb()
CVE-2024-58010 7.8 HIGH binfmt_flat: Fix integer overflow bug on 32 bit systems
CVE-2024-58013 7.8 HIGH Bluetooth: MGMT: Fix slab-use-after-free Read in mgmt_remove_adv_monitor_sync
CVE-2025-21791 7.8 HIGH vrf: use RCU protection in l3mdev_l3_out()
CVE-2025-21734 7.8 HIGH misc: fastrpc: Fix copy buffer page size
CVE-2024-58019 7.8 HIGH nvkm/gsp: correctly advance the read pointer of GSP message queue

Showing top 20 of 177 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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