CVE-2025-40027 Vulnerability Analysis & Exploit Details

CVE-2025-40027
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2025-40027 Details

Status: Awaiting Analysis

Last updated: 🕒 30 Oct 2025, 15:05 UTC
Originally published on: 🕙 28 Oct 2025, 10:15 UTC

Time between publication and last update: 2 days

CVSS Release:

CVE-2025-40027 Vulnerability Summary

CVE-2025-40027: In the Linux kernel, the following vulnerability has been resolved: net/9p: fix double req put in p9_fd_cancelled Syzkaller reports a KASAN issue as below: general protection fault, probably for non-canonical address 0xfbd59c0000000021: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0xdead000000000108-0xdead00000000010f] CPU: 0 PID: 5083 Comm: syz-executor.2 Not tainted 6.1.134-syzkaller-00037-g855bd1d7d838 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:__list_del include/linux/list.h:114 [inline] RIP: 0010:__list_del_entry include/linux/list.h:137 [inline] RIP: 0010:list_del include/linux/list.h:148 [inline] RIP: 0010:p9_fd_cancelled+0xe9/0x200 net/9p/trans_fd.c:734 Call Trace: <TASK> p9_client_flush+0x351/0x440 net/9p/client.c:614 p9_client_rpc+0xb6b/0xc70 net/9p/client.c:734 p9_client_version net/9p/client.c:920 [inline] p9_client_create+0xb51/0x1240 net/9p/client.c:1027 v9fs_session_init+0x1f0/0x18f0 fs/9p/v9fs.c:408 v9fs_mount+0xba/0xcb0 fs/9p/vfs_super.c:126 legacy_get_tree+0x108/0x220 fs/fs_context.c:632 vfs_get_tree+0x8e/0x300 fs/super.c:1573 do_new_mount fs/namespace.c:3056 [inline] path_mount+0x6a6/0x1e90 fs/namespace.c:3386 do_mount fs/namespace.c:3399 [inline] __do_sys_mount fs/namespace.c:3607 [inline] __se_sys_mount fs/namespace.c:3584 [inline] __x64_sys_mount+0x283/0x300 fs/namespace.c:3584 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 This happens because of a race condition between: - The 9p client sending an invalid flush request and later cleaning it up; - The 9p client in p9_read_work() canceled all pending requests. Thread 1 Thread 2 ... p9_client_create() ... p9_fd_create() ... p9_conn_create() ... // start Thread 2 INIT_WORK(&m->rq, p9_read_work); p9_read_work() ... p9_client_rpc() ... ... p9_conn_cancel() ... spin_lock(&m->req_lock); ... p9_fd_cancelled() ... ... spin_unlock(&m->req_lock); // status rewrite p9_client_cb(m->client, req, REQ_STATUS_ERROR) // first remove list_del(&req->req_list); ... spin_lock(&m->req_lock) ... // second remove list_del(&req->req_list); spin_unlock(&m->req_lock) ... Commit 74d6a5d56629 ("9p/trans_fd: Fix concurrency del of req_list in p9_fd_cancelled/p9_read_work") fixes a concurrency issue in the 9p filesystem client where the req_list could be deleted simultaneously by both p9_read_work and p9_fd_cancelled functions, but for the case where req->status equals REQ_STATUS_RCVD. Update the check for req->status in p9_fd_cancelled to skip processing not just received requests, but anything that is not SENT, as whatever changed the state from SENT also removed the request from its list. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. [updated the check from status == RECV || status == ERROR to status != SENT]

Assessing the Risk of CVE-2025-40027

Access Complexity Graph

The exploitability of CVE-2025-40027 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2025-40027

No exploitability data is available for CVE-2025-40027.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2025-40027, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2025-40027, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2025-40027 does not compromise confidentiality.
  • Integrity: None
    CVE-2025-40027 does not impact data integrity.
  • Availability: None
    CVE-2025-40027 does not affect system availability.

CVE-2025-40027 References

External References

CWE Common Weakness Enumeration

Unknown

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