{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40271", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.183Z", "datePublished": "2025-12-06T21:50:53.266Z", "dateUpdated": "2026-08-05T12:09:04.518Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:09:04.518Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/proc: fix uaf in proc_readdir_de()\n\nPde is erased from subdir rbtree through rb_erase(), but not set the node\nto EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE()\nset the erased node to EMPTY, then pde_subdir_next() will return NULL to\navoid uaf access.\n\nWe found an uaf issue while using stress-ng testing, need to run testcase\ngetdent and tun in the same time. The steps of the issue is as follows:\n\n1) use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current\n pde is tun3;\n\n2) in the [time windows] unregister netdevice tun3 and tun2, and erase\n them from rbtree. erase tun3 first, and then erase tun2. the\n pde(tun2) will be released to slab;\n\n3) continue to getdent process, then pde_subdir_next() will return\n pde(tun2) which is released, it will case uaf access.\n\nCPU 0 | CPU 1\n-------------------------------------------------------------------------\ntraverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2\nsys_getdents64() |\n iterate_dir() |\n proc_readdir() |\n proc_readdir_de() | snmp6_unregister_dev()\n pde_get(de); | proc_remove()\n read_unlock(&proc_subdir_lock); | remove_proc_subtree()\n | write_lock(&proc_subdir_lock);\n [time window] | rb_erase(&root->subdir_node, &parent->subdir);\n | write_unlock(&proc_subdir_lock);\n read_lock(&proc_subdir_lock); |\n next = pde_subdir_next(de); |\n pde_put(de); |\n de = next; //UAF |\n\nrbtree of dev_snmp6\n |\n pde(tun3)\n / \\\n NULL pde(tun2)" } ], "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 vulnerability is triggered entirely through local syscalls — `getdents64(2)` on a procfs directory racing against `unshare(2)`/rtnetlink operations that remove `/proc` entries. No network or remote-peer data is involved.\nAC:L - The attacker owns both sides of the race: one thread iterates `/proc/self/net/dev_snmp6` while another spins netdevice rename/unregister to erase entries, and the `dir_emit()` window can be stretched arbitrarily by backing the `getdents64` buffer with userfaultfd or FUSE so the reader stalls in `copy_to_user` while the neighbour pde is freed and the slab groomed. The sequence is unbounded and retryable.\nPR:L - Reading `/proc/self/net/dev_snmp6` requires no privilege at all, and the removal side needs only `CAP_NET_ADMIN` inside an attacker-created user+network namespace (`unshare -Urn`), which any unprivileged user obtains on default distro configurations. No real root in the init namespace is needed.\nUI:N - The attacker drives both the directory iteration and the proc-entry removal from its own threads; no victim action or cooperation is required.\nS:U - The corruption is confined to kernel heap objects managed by the same kernel security authority; there is no VM, IOMMU, or hypervisor boundary crossed.\nC:H - `dir_emit(ctx, de->name, de->namelen, ...)` reads the `char *name` pointer and `u8 namelen` out of the freed `proc_dir_entry` and copies up to 255 bytes from that pointer directly into the user's dirent buffer, giving a repeatable arbitrary-kernel-memory read into userspace once the slab object is reclaimed with attacker-influenced content.\nI:H - The use-after-free yields `refcount_inc()`/`refcount_dec_and_test()` on freed memory plus `pde_free()` performing `kfree(pde->data)`/`kfree(pde->name)` on pointers read from the reallocated object, providing arbitrary-free and heap-corruption primitives that are a standard basis for local privilege escalation.\nA:H - Dereferencing stale rbtree links into freed slab memory reliably produces a kernel oops/panic (as observed under stress-ng with getdents+tun), and the race can be re-run indefinitely to crash the system on demand." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/proc/generic.c" ], "versions": [ { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "1d1596d68a6f11d28f677eedf6cf5b17dbfeb491", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "c81d0385500446efe48c305bbb83d47f2ae23a50", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "4cba73c4c89219beef7685a47374bf88b1022369", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "6f2482745e510ae1dacc9b090194b9c5f918d774", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "67272c11f379d9aa5e0f6b16286b9d89b3f76046", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "623bb26127fb581a741e880e1e1a47d79aecb6f8", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "03de7ff197a3d0e17d0d5c58fdac99a63cba8110", "status": "affected", "versionType": "git" }, { "version": "710585d4922fd315f2cada8fbe550ae8ed23e994", "lessThan": "895b4c0c79b092d732544011c3cecaf7322c36a1", "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/proc/generic.c" ], "versions": [ { "version": "3.19", "status": "affected" }, { "version": "0", "lessThan": "3.19", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.302", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.247", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.197", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.159", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.117", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.59", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.9", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "3.19", "versionEndExcluding": "5.4.302" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "5.10.247" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "5.15.197" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "6.1.159" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "6.6.117" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "6.12.59" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "6.17.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/1d1596d68a6f11d28f677eedf6cf5b17dbfeb491" }, { "url": "https://git.kernel.org/stable/c/c81d0385500446efe48c305bbb83d47f2ae23a50" }, { "url": "https://git.kernel.org/stable/c/4cba73c4c89219beef7685a47374bf88b1022369" }, { "url": "https://git.kernel.org/stable/c/6f2482745e510ae1dacc9b090194b9c5f918d774" }, { "url": "https://git.kernel.org/stable/c/67272c11f379d9aa5e0f6b16286b9d89b3f76046" }, { "url": "https://git.kernel.org/stable/c/623bb26127fb581a741e880e1e1a47d79aecb6f8" }, { "url": "https://git.kernel.org/stable/c/03de7ff197a3d0e17d0d5c58fdac99a63cba8110" }, { "url": "https://git.kernel.org/stable/c/895b4c0c79b092d732544011c3cecaf7322c36a1" } ], "title": "fs/proc: fix uaf in proc_readdir_de()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-06-02T13:00:17.378Z" }, "affected": [ { "vendor": "Siemens", "product": "RUGGEDCOM RST2428P", "versions": [ { "status": "affected", "version": "0", "lessThan": "V4.0", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-253495.html" } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T19:37:49.226666Z", "id": "CVE-2025-40271", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T19:37:59.970Z" } } ] } }