{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21889", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.782Z", "datePublished": "2025-03-27T14:57:15.897Z", "dateUpdated": "2026-08-05T11:55:10.093Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:10.093Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Add RCU read lock protection to perf_iterate_ctx()\n\nThe perf_iterate_ctx() function performs RCU list traversal but\ncurrently lacks RCU read lock protection. This causes lockdep warnings\nwhen running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y:\n\n\tWARNING: suspicious RCU usage\n\tkernel/events/core.c:8168 RCU-list traversed in non-reader section!!\n\n\t Call Trace:\n\t lockdep_rcu_suspicious\n\t ? perf_event_addr_filters_apply\n\t perf_iterate_ctx\n\t perf_event_exec\n\t begin_new_exec\n\t ? load_elf_phdrs\n\t load_elf_binary\n\t ? lock_acquire\n\t ? find_held_lock\n\t ? bprm_execve\n\t bprm_execve\n\t do_execveat_common.isra.0\n\t __x64_sys_execve\n\t do_syscall_64\n\t entry_SYSCALL_64_after_hwframe\n\nThis protection was previously present but was removed in commit\nbd2756811766 (\"perf: Rewrite core context handling\"). Add back the\nnecessary rcu_read_lock()/rcu_read_unlock() pair around\nperf_iterate_ctx() call in perf_event_exec().\n\n[ mingo: Use scoped_guard() as suggested by Peter ]" } ], "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 vulnerable path is entered through local syscalls only — `execve()` reaching `perf_event_exec()` via `begin_new_exec()`, with the racing side driven by `perf_event_open()`/`close()`. No network or remote input reaches this code.\nAC:L - The attacker controls both sides of the race, looping `execve()` in one process while closing perf event fds attached to it from another, and can widen the window arbitrarily via CPU pinning and the cross-CPU IPI that `perf_event_stop()` issues inside the unprotected walk. Nothing about the trigger depends on conditions outside the attacker's influence.\nPR:L - An ordinary unprivileged user suffices: `sysctl_perf_event_paranoid` defaults to 2, which permits task-bound user-space perf events on same-uid processes, and no capability is checked anywhere on the `execve()` side of the race.\nUI:N - Both the exec'ing process and the event-closing process are attacker-controlled; no victim action or cooperation is needed.\nS:U - The corruption stays within the kernel's own security authority — a standard local kernel memory-safety flaw with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The unprotected RCU walk dereferences a freed `struct perf_event`, and the reclaimed slot can be groomed with attacker-sprayed perf events, giving a use-after-free read primitive that leaks kernel memory and pointers.\nI:H - `perf_event_addr_filters_exec()` writes into the freed object — zeroing `addr_filter_ranges[count].start/.size` through a pointer read out of reclaimed memory and incrementing `addr_filters_gen` — yielding an attacker-influenced kernel write suitable for privilege escalation.\nA:H - Traversing a freed list entry corrupts the walk and readily produces list corruption, an oops, or a full kernel panic, and the race can be retriggered in a loop." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/events/core.c" ], "versions": [ { "version": "bd27568117664b8b3e259721393df420ed51f57b", "lessThan": "f390c2eea571945f357a2d3b9fcb1c015767132e", "status": "affected", "versionType": "git" }, { "version": "bd27568117664b8b3e259721393df420ed51f57b", "lessThan": "a2475ccad6120546ea45dbcd6cd1f74dc565ef6b", "status": "affected", "versionType": "git" }, { "version": "bd27568117664b8b3e259721393df420ed51f57b", "lessThan": "dd536566dda9a551fc2a2acfab5313a5bb13ed02", "status": "affected", "versionType": "git" }, { "version": "bd27568117664b8b3e259721393df420ed51f57b", "lessThan": "0fe8813baf4b2e865d3b2c735ce1a15b86002c74", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/events/core.c" ], "versions": [ { "version": "6.2", "status": "affected" }, { "version": "0", "lessThan": "6.2", "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": "6.2", "versionEndExcluding": "6.6.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.12.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.13.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f390c2eea571945f357a2d3b9fcb1c015767132e" }, { "url": "https://git.kernel.org/stable/c/a2475ccad6120546ea45dbcd6cd1f74dc565ef6b" }, { "url": "https://git.kernel.org/stable/c/dd536566dda9a551fc2a2acfab5313a5bb13ed02" }, { "url": "https://git.kernel.org/stable/c/0fe8813baf4b2e865d3b2c735ce1a15b86002c74" } ], "title": "perf/core: Add RCU read lock protection to perf_iterate_ctx()", "x_generator": { "engine": "bippy-1.2.0" } } } }