{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21887", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.782Z", "datePublished": "2025-03-27T14:57:14.524Z", "dateUpdated": "2026-08-05T11:55:09.027Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:09.027Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up\n\nThe issue was caused by dput(upper) being called before\novl_dentry_update_reval(), while upper->d_flags was still\naccessed in ovl_dentry_remote().\n\nMove dput(upper) after its last use to prevent use-after-free.\n\nBUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline]\nBUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167\n\nCall Trace:\n \n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0xc3/0x620 mm/kasan/report.c:488\n kasan_report+0xd9/0x110 mm/kasan/report.c:601\n ovl_dentry_remote fs/overlayfs/util.c:162 [inline]\n ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167\n ovl_link_up fs/overlayfs/copy_up.c:610 [inline]\n ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170\n ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223\n ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136\n vfs_rename+0xf84/0x20a0 fs/namei.c:4893\n...\n " } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is reached through local syscalls only — mounting overlayfs (and a FUSE upper) and issuing rename(2)/open(O_TRUNC) to trigger copy-up. No network-facing component processes attacker data on this path.\nAC:L - The attacker controls both halves of the timing: the FUSE server sets entry_valid=0 so dput() deterministically kills the dentry, and it stalls the SETATTR in ovl_set_timestamps() to hold the window open arbitrarily long for RCU to free the object and for a heap spray to refill the slot. No condition depends on chance or on unrelated system state.\nPR:L - Both overlayfs and fuse are FS_USERNS_MOUNT, so an ordinary unprivileged user can create the whole setup inside `unshare -Urm`, and several distros permit unprivileged overlayfs outright; the copy-up path contains no capability check. Some form of local account is required, so not None.\nUI:N - The attacker performs the mount, the FUSE service, and the rename entirely on their own, within their own namespace. No victim action of any kind is needed.\nS:U - The corrupted and disclosed state is kernel memory reached from a kernel-mode fault; the impact stays within the kernel's own security authority with no crossing into a hypervisor, IOMMU, or other authority.\nC:H - This is a slab use-after-free read of a freed struct dentry whose contents the attacker can shape by spraying the dentry_cache during the FUSE-controlled stall, and the read value is propagated into live VFS state, yielding an observable oracle on freed kernel memory. Per UAF scoring guidance this is High.\nI:H - Content read out of a freed, attacker-refillable slab object is written into a live dentry's d_flags, corrupting VFS revalidation state (stale dentries accepted on remote upper/lower filesystems). Use-after-free primitives of this class are treated as High integrity impact.\nA:H - KASAN confirms a slab-use-after-free; once the dentry slab page is returned to the page allocator — which the attacker can encourage by draining the dcache during the stall — the dereference faults and oopses the kernel, and the fault occurs with the upper directory inode lock held, wedging further operations." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/overlayfs/copy_up.c" ], "versions": [ { "version": "714ba10a6dd19752a349e59aa875f3288ccb59b9", "lessThan": "f77618291836168eca99e89cd175256f928f5e64", "status": "affected", "versionType": "git" }, { "version": "62f29ca45f832e281fc14966ac25f6ff3bd121ca", "lessThan": "4b49d939b5a79117f939b77cc67efae2694d9799", "status": "affected", "versionType": "git" }, { "version": "e4f2a1feebb3f209a0fca82aa53507a5b8be4d53", "lessThan": "a7c41830ffcd17b2177a95a9b99b270302090c35", "status": "affected", "versionType": "git" }, { "version": "b07d5cc93e1b28df47a72c519d09d0a836043613", "lessThan": "64455c8051c3aedc71abb7ec8d47c80301f99f00", "status": "affected", "versionType": "git" }, { "version": "b07d5cc93e1b28df47a72c519d09d0a836043613", "lessThan": "3594aad97e7be2557ca9fa9c931b206b604028c8", "status": "affected", "versionType": "git" }, { "version": "b07d5cc93e1b28df47a72c519d09d0a836043613", "lessThan": "60b4b5c1277fc491da9e1e7abab307bfa39c2db7", "status": "affected", "versionType": "git" }, { "version": "b07d5cc93e1b28df47a72c519d09d0a836043613", "lessThan": "c84e125fff2615b4d9c259e762596134eddd2f27", "status": "affected", "versionType": "git" }, { "version": "33ab4dd6202f359558a0a2678b94d1b9994c17e5", "status": "affected", "versionType": "git" }, { "version": "1ecdc55e5cd9f70f8d7513802971d4cffb9f77af", "status": "affected", "versionType": "git" }, { "version": "5.10.188", "lessThan": "5.10.247", "status": "affected", "versionType": "semver" }, { "version": "5.15.121", "lessThan": "5.15.179", "status": "affected", "versionType": "semver" }, { "version": "6.1.39", "lessThan": "6.1.130", "status": "affected", "versionType": "semver" }, { "version": "6.3.13", "lessThan": "6.4", "status": "affected", "versionType": "semver" }, { "version": "6.4.4", "lessThan": "6.5", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/overlayfs/copy_up.c" ], "versions": [ { "version": "6.5", "status": "affected" }, { "version": "0", "lessThan": "6.5", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.247", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.179", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.130", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.81", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.18", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.6", "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": "5.10.188", "versionEndExcluding": "5.10.247" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.121", "versionEndExcluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.39", "versionEndExcluding": "6.1.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.6.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.12.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.13.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.14" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f77618291836168eca99e89cd175256f928f5e64" }, { "url": "https://git.kernel.org/stable/c/4b49d939b5a79117f939b77cc67efae2694d9799" }, { "url": "https://git.kernel.org/stable/c/a7c41830ffcd17b2177a95a9b99b270302090c35" }, { "url": "https://git.kernel.org/stable/c/64455c8051c3aedc71abb7ec8d47c80301f99f00" }, { "url": "https://git.kernel.org/stable/c/3594aad97e7be2557ca9fa9c931b206b604028c8" }, { "url": "https://git.kernel.org/stable/c/60b4b5c1277fc491da9e1e7abab307bfa39c2db7" }, { "url": "https://git.kernel.org/stable/c/c84e125fff2615b4d9c259e762596134eddd2f27" } ], "title": "ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2025-21887", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-03-27T16:59:58.510815Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-03-27T17:08:22.888Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:38:40.259Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:40:26.912Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html" } ] } ] } }