CVE-2025-40027

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2025-10-28. the CNA's CVSS baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
Trending — 5 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

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: 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]

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

October 28, 2025

Last Modified

August 5, 2026

Advisory Details (9)

Auto-updated Jul 31, 2026
No patch confirmed yet.
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c1db864270eb7fea94a9ef201da0c9dc1cbab7b8
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a5901a0dfb5964525990106706ae8b98db098226
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/94797b84cb9985022eb9cb3275c9497fbc883bb6
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/716dceb19a9f8ff6c9d3aee5a771a93d6a47a0b6
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/674b56aa57f9379854cb6798c3bbcef7e7b51ab7
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5c64c0b7b3446f7ed088a13bc8d7487d66534cbb
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/448db01a48e1cdbbc31c995716a5dac1e52ba036
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/284e67a93b8c48952b6fc82129a8d3eb9dc73b06
generic

net/9p: fix double req put in p9_fd_cancelled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0e0097005abc02c9f262370674f855625f4f3fb4

Vendor Advisories for CVE-2025-40027(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(28)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1049.52.1) @ noble2026-07-30ubuntu
ubuntulinux-tools-gcp-64k-6.17 (6.17.0-1004.4) @ questing2026-07-30ubuntu
ubuntulinux-tools-intel-iotg-5.15 (5.15.0.1095.95) @ jammy2026-07-30ubuntu
ubuntulinux-tools-raspi-6.17 (6.17.0-1005.5) @ questing2026-07-30ubuntu
ubuntulinux-tools-azure-fips-5.15 (5.15.0.1109.94) @ jammy2026-07-30ubuntu
ubuntulinux-tools-raspi-nolpae (5.15.0.1097.95) @ jammy2026-07-30ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1051.57) @ noble2026-07-30ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1052.58+fips1) @ noble2026-07-30ubuntu
ubuntulinux-tools-realtime-hwe-22.04 (6.8.1-1045.46~22.04.1) @ jammy2026-07-30ubuntu
ubuntulinux-tools-azure-edge (6.8.0-1051.57~22.04.1) @ jammy2026-07-30ubuntu
ubuntulinux-tools-aws-edge (6.8.0-1050.53~22.04.1) @ jammy2026-07-30ubuntu
ubuntulinux-tools-azure-lts-22.04 (5.15.0.1109.107) @ jammy2026-07-30ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2040.41) @ noble2026-07-30ubuntu
ubuntulinux-tools-azure-edge (5.15.0.1110.119~20.04.1) @ focal2026-07-30ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1029.30) @ noble2026-07-30ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.17.0-7.7) @ questing2026-07-30ubuntu
ubuntulinux-virtual-hwe-20.04-edge (5.15.0.170.159) @ jammy2026-07-30ubuntu
ubuntulinux-tools-realtime-5.15 (5.15.0.1099.103) @ jammy2026-07-30ubuntu
ubuntulinux-tools-gcp-fips-5.15 (5.15.0.1100.90) @ jammy2026-07-30ubuntu
ubuntulinux-tools-nvidia-tegra-rt-5.15 (5.15.0.1052.52~20.04.2) @ focal2026-07-30ubuntu
ubuntulinux-tools-aws-edge (5.15.0.1100.107~20.04.1) @ focal2026-07-30ubuntu
ubuntulinux-tools-oracle-lts-22.04 (5.15.0.1097.93) @ jammy2026-07-30ubuntu
ubuntulinux-tools-nvidia-tegra-igx-rt-5.15 (5.15.0.1041.43) @ jammy2026-07-30ubuntu
ubuntulinux-tools-intel-iotg-edge (5.15.0.1095.101~20.04.1) @ focal2026-07-30ubuntu
ubuntulinux-tools-nvidia-lowlatency-5.15 (5.15.0.1095.95) @ jammy2026-07-30ubuntu
ubuntulinux-virtual-6.8 (6.8.0-106.106) @ noble2026-07-30ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1052.55+fips1) @ noble2026-07-30ubuntu
linuxKernel @ 5.4.301—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 13× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 142 total refreshes for this CVE.

  1. 2026-08-05 12:54 UTCEG score recompute
  2. 2026-08-05 12:54 UTCVendor advisory
  3. 2026-08-05 12:54 UTCGHSA enrichment
  4. 2026-08-04 15:09 UTCEPSS rescore
  5. 2026-08-04 10:37 UTCEPSS rescore
  6. 2026-08-03 10:35 UTCEPSS rescore
  7. 2026-08-02 02:26 UTCEPSS rescore
  8. 2026-08-01 04:15 UTCEPSS rescore
  9. 2026-07-30 16:27 UTCEPSS rescore
  10. 2026-07-30 06:31 UTCEG score recompute▲ 7.80
  11. 2026-07-30 06:31 UTCVendor advisory
  12. 2026-07-30 06:30 UTCGHSA enrichment
  13. 2026-07-30 06:18 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  14. 2026-07-30 01:29 UTCEPSS rescore
  15. 2026-07-28 15:35 UTCEPSS rescore
  16. 2026-07-27 08:39 UTCOSV refresh
  17. 2026-07-26 14:54 UTCEPSS rescore
  18. 2026-07-25 14:17 UTCEPSS rescore
  19. 2026-07-25 14:17 UTCEPSS rescore
  20. 2026-07-24 14:17 UTCEPSS rescore
  21. 2026-07-23 02:55 UTCEG score recompute
  22. 2026-07-22 14:07 UTCEPSS rescore
  23. 2026-07-22 14:07 UTCEPSS rescore
  24. 2026-07-21 15:24 UTCEPSS rescore
  25. 2026-07-20 17:07 UTCEPSS rescore
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  1. 2026-07-19 14:30 UTCEPSS rescore
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  16. 2026-07-11 08:27 UTCEPSS rescore
  17. 2026-07-11 08:27 UTCEPSS rescore
  18. 2026-07-10 03:23 UTCOSV refresh
  19. 2026-07-09 19:09 UTCEPSS rescore
  20. 2026-07-09 19:09 UTCEPSS rescore
  21. 2026-07-07 13:45 UTCEPSS rescore
  22. 2026-07-06 16:27 UTCEPSS rescore
  23. 2026-07-06 16:27 UTCEPSS rescore
  24. 2026-07-06 02:23 UTCEPSS rescore
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  26. 2026-07-04 06:30 UTCEPSS rescore
  27. 2026-07-01 15:06 UTCEPSS rescore
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  29. 2026-06-30 23:22 UTCEPSS rescore
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  31. 2026-06-29 14:06 UTCEPSS rescore
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  47. 2026-06-21 14:56 UTCEPSS rescore
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  49. 2026-06-21 14:01 UTCOSV refresh
  50. 2026-06-21 01:59 UTCEPSS rescore
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  52. 2026-06-19 19:25 UTCEPSS rescore
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  54. 2026-06-18 17:52 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2025-40027?
CVE-2025-40027 is a high vulnerability published on October 28, 2025. In the Linux kernel, the following vulnerability has been resolved: net/9p: fix double req put in p9fdcancelled Syzkaller reports a KASAN issue as below: general protection fault, probably for non-canonical address 0xfbd59c0000000021: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: maybe…
When was CVE-2025-40027 disclosed?
CVE-2025-40027 was first published in the National Vulnerability Database on October 28, 2025, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-40027 actively exploited?
CVE-2025-40027 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.3% of all scored CVEs.
What is the CVSS score of CVE-2025-40027?
CVE-2025-40027 has a CVSS v4.0 base score of 7.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2025-40027?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-40027, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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