{"id":"CVE-2025-21796","revision":null,"records":[{"revision":"17d2fc8ca15b42cd96b03847b3bd1911","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-21796","aliases":[],"title":"nfsd: clear acl_access/acl_default after releasing them","description":"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.","state":0,"publishedAt":"2025-02-27T02:18:32.191+00:00","modifiedAt":"2026-10-15T01:04:29.859+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs2acl.c\",\n                        \"fs/nfsd/nfs3acl.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"8a1737ae42c928384ab6447f6ee1a882510e85fa\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"6f7cfee1a316891890c505563aa54f3476db52fd\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"2e59b2b68782519560b3d6a41dd66a3d01a01cd3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"55d947315fb5f67a35e4e1d3e01bb886b9c6decf\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"f8d871523142f7895f250a856f8c4a4181614510\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"1fd94884174bd20beb1773990fd3b1aa877688d9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"a257cdd0e2179630d3201c32ba14d7fcb3c3a055\",\n                            \"lessThan\": \"7faf14a7b0366f153284db0ad3347c457ea70136\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs2acl.c\",\n                        \"fs/nfsd/nfs3acl.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.13\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.13\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.235\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.179\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.129\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.79\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.16\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.13.4\",\n                            \"lessThanOrEqual\": \"6.13.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.14\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/8a1737ae42c928384ab6447f6ee1a882510e85fa","https://git.kernel.org/stable/c/6f7cfee1a316891890c505563aa54f3476db52fd","https://git.kernel.org/stable/c/2e59b2b68782519560b3d6a41dd66a3d01a01cd3","https://git.kernel.org/stable/c/55d947315fb5f67a35e4e1d3e01bb886b9c6decf","https://git.kernel.org/stable/c/f8d871523142f7895f250a856f8c4a4181614510","https://git.kernel.org/stable/c/1fd94884174bd20beb1773990fd3b1aa877688d9","https://git.kernel.org/stable/c/7faf14a7b0366f153284db0ad3347c457ea70136"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21796","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-21796","identifiers":["CVE-2025-21796"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-09T19:02:11.0282238+00:00","complete":true,"records":1772,"lastAttemptAt":"2026-11-09T19:02:11.0282238+00:00","lastSuccessAt":"2026-11-09T19:02:11.2511726+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:11.2511728+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-24e6fde7b744113daefb8f6135035fb8a5c69c9617c9c0d40574a0376532ffd3-da82b7f3c08c0a1c809bacbfac0a567c645c18f0205247304bfc7e4ee4c02653","complete":true,"records":421491,"lastAttemptAt":"2026-11-09T19:02:10.4293016+00:00","lastSuccessAt":"2026-11-09T18:02:17.6122603+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:10.4293016+00:00","snapshotPublishedAt":"2026-11-09T17:19:01+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-f1df18dfb77f437e9e2ee1dd548e1f15","complete":false,"records":13655,"lastAttemptAt":"2026-11-09T19:14:35.1855237+00:00","lastSuccessAt":"2026-11-09T19:14:35.178+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:14:35.178+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13398,"expectedIdentifiers":13707,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-09T19:02:11.0282238+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-09T19:02:11.0282238+00:00","lastSuccessAt":"2026-11-09T19:02:11.2551731+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:11.2551735+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-9c7aae9a77ad4fe48f16e3014ae326fa","complete":true,"records":13667,"lastAttemptAt":"2026-11-09T19:02:43.2420437+00:00","lastSuccessAt":"2026-11-09T19:02:43.234+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:43.234+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13707,"expectedIdentifiers":13707,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T19:02:10.7853332+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:10.7853332+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-712163772d637a9cfaa34d4241efb9e9d0ccd6149596c672c613d362f44af841","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T19:02:10.5860178+00:00","lastSuccessAt":"2026-11-09T18:02:23.0088273+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:10.5860178+00:00","snapshotPublishedAt":"2026-11-09T17:03:01+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-761ecc9061239b0da572dc9254c6f384c1d19339eb08408c436647a2f26129e9","complete":true,"records":3064,"lastAttemptAt":"2026-11-09T19:02:10.8954054+00:00","lastSuccessAt":"2026-11-09T17:05:03.4044794+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:10.8954054+00:00","snapshotPublishedAt":"2026-11-09T16:33:20+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-e3fec63b2a5926ae79916bc9569f5c1069b095db78f2be319f909e69e8e6d7d3","complete":true,"records":231313,"lastAttemptAt":"2026-11-09T19:02:10.6843987+00:00","lastSuccessAt":"2026-11-09T18:04:48.1910635+00:00","error":null,"lastVerifiedAt":"2026-11-09T19:02:10.6843987+00:00","snapshotPublishedAt":"2026-11-09T17:33:10+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}