CVE-2025-40071

Local service hang via synchronous MSC wait

Published Oct 28, 2025 · Updated Oct 28, 2025

Denial of service in Linux kernel n_gsm allows local users to hang GSM DLC handling by opening an affected basic-mode channel. During gsm_queue processing, gsm_dlci_open calls gsm_modem_update, which synchronously waits for an MSC reply on the same input queue it blocks. The hang requires local access that opens a DLC channel with basic encoding; advanced encoding and convergence layer type 2 do not enter the waiting path.

CVSS severity6.1
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux kernel n_gsm allows local users to hang GSM DLC handling by opening an affected basic-mode channel. During gsm_queue processing, gsm_dlci_open calls gsm_modem_update, which synchronously waits for an MSC reply on the same input queue it blocks. The hang requires local access that opens a DLC channel with basic encoding; advanced encoding and convergence layer type 2 do not enter the waiting path.

The record

CVE
CVE-2025-40071
Published
Oct 28, 2025
Updated
Oct 28, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=48473802506d2d6151f59e0e764932b33b53cb3b <3cf0b3c243e56bc43be560617416c1d9f301f44c
  2. Affected versionversion=48473802506d2d6151f59e0e764932b33b53cb3b <5416e89b81b00443cb03c88df8da097ae091a141
  3. Affected versionversion=48473802506d2d6151f59e0e764932b33b53cb3b <c36785f9de03df56ff9b8eca30fa681a12b2310d
  4. Affected versionversion=48473802506d2d6151f59e0e764932b33b53cb3b <c5a2791a7f11939f05f95c01f0aec0c55bbf28d5
  5. Affected versionversion=5.18
  6. Affected versionversion=920e849b7d23ced84c9d11e11e2449e34973cfb8
  7. Affected versionversion=e83b4e1540469babeffcfd44a605cf8a61542598

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=48473802506d2d6151f59e0e764932b33b53cb3b <3cf0b3c243e56bc43be560617416c1d9f301f44c; version=48473802506d2d6151f59e0e764932b33b53cb3b <5416e89b81b00443cb03c88df8da097ae091a141; version=48473802506d2d6151f59e0e764932b33b53cb3b <c36785f9de03df56ff9b8eca30fa681a12b2310d; version=48473802506d2d6151f59e0e764932b33b53cb3b <c5a2791a7f11939f05f95c01f0aec0c55bbf28d5; version=5.18; version=920e849b7d23ced84c9d11e11e2449e34973cfb8; version=e83b4e1540469babeffcfd44a605cf8a61542598

Published CVSS scores

6.1Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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