{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21796","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-12-29T08:45:45.768Z","datePublished":"2025-02-27T02:18:32.191Z","dateUpdated":"2026-05-12T12:03:56.109Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T21:06:39.968Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: clear acl_access/acl_default after releasing them\n\nIf getting acl_default fails, acl_access and acl_default will be released\nsimultaneously. However, acl_access will still retain a pointer pointing\nto the released posix_acl, which will trigger a WARNING in\nnfs3svc_release_getacl like this:\n\n------------[ cut here ]------------\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 26 PID: 3199 at lib/refcount.c:28\nrefcount_warn_saturate+0xb5/0x170\nModules linked in:\nCPU: 26 UID: 0 PID: 3199 Comm: nfsd Not tainted\n6.12.0-rc6-00079-g04ae226af01f-dirty #8\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.16.1-2.fc37 04/01/2014\nRIP: 0010:refcount_warn_saturate+0xb5/0x170\nCode: cc cc 0f b6 1d b3 20 a5 03 80 fb 01 0f 87 65 48 d8 00 83 e3 01 75\ne4 48 c7 c7 c0 3b 9b 85 c6 05 97 20 a5 03 01 e8 fb 3e 30 ff <0f> 0b eb\ncd 0f b6 1d 8a3\nRSP: 0018:ffffc90008637cd8 EFLAGS: 00010282\nRAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83904fde\nRDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88871ed36380\nRBP: ffff888158beeb40 R08: 0000000000000001 R09: fffff520010c6f56\nR10: ffffc90008637ab7 R11: 0000000000000001 R12: 0000000000000001\nR13: ffff888140e77400 R14: ffff888140e77408 R15: ffffffff858b42c0\nFS:  0000000000000000(0000) GS:ffff88871ed00000(0000)\nknlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000562384d32158 CR3: 000000055cc6a000 CR4: 00000000000006f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n <TASK>\n ? refcount_warn_saturate+0xb5/0x170\n ? __warn+0xa5/0x140\n ? refcount_warn_saturate+0xb5/0x170\n ? report_bug+0x1b1/0x1e0\n ? handle_bug+0x53/0xa0\n ? exc_invalid_op+0x17/0x40\n ? asm_exc_invalid_op+0x1a/0x20\n ? tick_nohz_tick_stopped+0x1e/0x40\n ? refcount_warn_saturate+0xb5/0x170\n ? refcount_warn_saturate+0xb5/0x170\n nfs3svc_release_getacl+0xc9/0xe0\n svc_process_common+0x5db/0xb60\n ? __pfx_svc_process_common+0x10/0x10\n ? __rcu_read_unlock+0x69/0xa0\n ? __pfx_nfsd_dispatch+0x10/0x10\n ? svc_xprt_received+0xa1/0x120\n ? xdr_init_decode+0x11d/0x190\n svc_process+0x2a7/0x330\n svc_handle_xprt+0x69d/0x940\n svc_recv+0x180/0x2d0\n nfsd+0x168/0x200\n ? __pfx_nfsd+0x10/0x10\n kthread+0x1a2/0x1e0\n ? kthread+0xf4/0x1e0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x34/0x60\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n </TASK>\nKernel panic - not syncing: kernel: panic_on_warn set ...\n\nClear acl_access/acl_default after posix_acl_release is called to prevent\nUAF from being triggered."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs2acl.c","fs/nfsd/nfs3acl.c"],"versions":[{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"8a1737ae42c928384ab6447f6ee1a882510e85fa","status":"affected","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"6f7cfee1a316891890c505563aa54f3476db52fd","status":"affected","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"2e59b2b68782519560b3d6a41dd66a3d01a01cd3","status":"affected","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"55d947315fb5f67a35e4e1d3e01bb886b9c6decf","status":"affected","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"f8d871523142f7895f250a856f8c4a4181614510","status":"affected","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"1fd94884174bd20beb1773990fd3b1aa877688d9","status":"affected","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","lessThan":"7faf14a7b0366f153284db0ad3347c457ea70136","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs2acl.c","fs/nfsd/nfs3acl.c"],"versions":[{"version":"2.6.13","status":"affected"},{"version":"0","lessThan":"2.6.13","status":"unaffected","versionType":"semver"},{"version":"5.10.235","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.179","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.129","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.79","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.16","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.4","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.10.235"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.15.179"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.1.129"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.6.79"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.12.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.13.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.14"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/8a1737ae42c928384ab6447f6ee1a882510e85fa"},{"url":"https://git.kernel.org/stable/c/6f7cfee1a316891890c505563aa54f3476db52fd"},{"url":"https://git.kernel.org/stable/c/2e59b2b68782519560b3d6a41dd66a3d01a01cd3"},{"url":"https://git.kernel.org/stable/c/55d947315fb5f67a35e4e1d3e01bb886b9c6decf"},{"url":"https://git.kernel.org/stable/c/f8d871523142f7895f250a856f8c4a4181614510"},{"url":"https://git.kernel.org/stable/c/1fd94884174bd20beb1773990fd3b1aa877688d9"},{"url":"https://git.kernel.org/stable/c/7faf14a7b0366f153284db0ad3347c457ea70136"}],"title":"nfsd: 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