Vulnerability-Lookup

GHSA-MCF6-FPVV-XXR4

Vulnerability from github – Published: 2025-03-27 15:31 – Updated: 2025-10-29 18:30

Details

In the Linux kernel, the following vulnerability has been resolved:

perf/core: Add RCU read lock protection to perf_iterate_ctx()

The perf_iterate_ctx() function performs RCU list traversal but currently lacks RCU read lock protection. This causes lockdep warnings when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y:

WARNING: suspicious RCU usage
kernel/events/core.c:8168 RCU-list traversed in non-reader section!!

 Call Trace:
  lockdep_rcu_suspicious
  ? perf_event_addr_filters_apply
  perf_iterate_ctx
  perf_event_exec
  begin_new_exec
  ? load_elf_phdrs
  load_elf_binary
  ? lock_acquire
  ? find_held_lock
  ? bprm_execve
  bprm_execve
  do_execveat_common.isra.0
  __x64_sys_execve
  do_syscall_64
  entry_SYSCALL_64_after_hwframe

This protection was previously present but was removed in commit bd2756811766 ("perf: Rewrite core context handling"). Add back the necessary rcu_read_lock()/rcu_read_unlock() pair around perf_iterate_ctx() call in perf_event_exec().

[ mingo: Use scoped_guard() as suggested by Peter ]

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-21889"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-03-27T15:15:56Z",
    "severity": "MODERATE"
  },
  "details": "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 ]",
  "id": "GHSA-mcf6-fpvv-xxr4",
  "modified": "2025-10-29T18:30:28Z",
  "published": "2025-03-27T15:31:12Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21889"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0fe8813baf4b2e865d3b2c735ce1a15b86002c74"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a2475ccad6120546ea45dbcd6cd1f74dc565ef6b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dd536566dda9a551fc2a2acfab5313a5bb13ed02"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f390c2eea571945f357a2d3b9fcb1c015767132e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-21889 (GCVE-0-2025-21889)

Vulnerability from cvelistv5 – Published: 2025-03-27 14:57 – Updated: 2026-08-05 11:55

Title

perf/core: Add RCU read lock protection to perf_iterate_ctx()

Summary

In the Linux kernel, the following vulnerability has been resolved: perf/core: Add RCU read lock protection to perf_iterate_ctx() The perf_iterate_ctx() function performs RCU list traversal but currently lacks RCU read lock protection. This causes lockdep warnings when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y: WARNING: suspicious RCU usage kernel/events/core.c:8168 RCU-list traversed in non-reader section!! Call Trace: lockdep_rcu_suspicious ? perf_event_addr_filters_apply perf_iterate_ctx perf_event_exec begin_new_exec ? load_elf_phdrs load_elf_binary ? lock_acquire ? find_held_lock ? bprm_execve bprm_execve do_execveat_common.isra.0 __x64_sys_execve do_syscall_64 entry_SYSCALL_64_after_hwframe This protection was previously present but was removed in commit bd2756811766 ("perf: Rewrite core context handling"). Add back the necessary rcu_read_lock()/rcu_read_unlock() pair around perf_iterate_ctx() call in perf_event_exec(). [ mingo: Use scoped_guard() as suggested by Peter ]

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/f390c2eea571945f3…
https://git.kernel.org/stable/c/a2475ccad6120546e…
https://git.kernel.org/stable/c/dd536566dda9a551f…
https://git.kernel.org/stable/c/0fe8813baf4b2e865…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bd27568117664b8b3e259721393df420ed51f57b , < f390c2eea571945f357a2d3b9fcb1c015767132e (git) Affected: bd27568117664b8b3e259721393df420ed51f57b , < a2475ccad6120546ea45dbcd6cd1f74dc565ef6b (git) Affected: bd27568117664b8b3e259721393df420ed51f57b , < dd536566dda9a551fc2a2acfab5313a5bb13ed02 (git) Affected: bd27568117664b8b3e259721393df420ed51f57b , < 0fe8813baf4b2e865d3b2c735ce1a15b86002c74 (git)
Linux	Linux	Affected: 6.2 Unaffected: 0 , < 6.2 (semver) Unaffected: 6.6.81 , ≤ 6.6.* (semver) Unaffected: 6.12.18 , ≤ 6.12.* (semver) Unaffected: 6.13.6 , ≤ 6.13.* (semver) Unaffected: 6.14 , ≤ * (original_commit_for_fix)

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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/core.c"
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              "versionType": "git"
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              "status": "unaffected",
              "version": "6.12.18",
              "versionType": "semver"
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              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
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          "nodes": [
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                  "versionEndExcluding": "6.6.81",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
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          "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 ]"
        }
      ],
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          },
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            {
              "lang": "en",
              "value": "AV:L - The vulnerable path is entered through local syscalls only \u2014 `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\u0027s 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\u0027ing process and the event-closing process are attacker-controlled; no victim action or cooperation is needed.\nS:U - The corruption stays within the kernel\u0027s own security authority \u2014 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 \u2014 zeroing `addr_filter_ranges[count].start/.size` through a pointer read out of reclaimed memory and incrementing `addr_filters_gen` \u2014 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."
            }
          ]
        }
      ],
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        "dateUpdated": "2026-08-05T11:55:10.093Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/0fe8813baf4b2e865d3b2c735ce1a15b86002c74"
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      "title": "perf/core: Add RCU read lock protection to perf_iterate_ctx()",
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    "cveId": "CVE-2025-21889",
    "datePublished": "2025-03-27T14:57:15.897Z",
    "dateReserved": "2024-12-29T08:45:45.782Z",
    "dateUpdated": "2026-08-05T11:55:10.093Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-MCF6-FPVV-XXR4

CVE-2025-21889 (GCVE-0-2025-21889)

Tags

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