CVE-2024-49946

System hang via PPP softirq self-deadlock

Published Oct 21, 2024 · Updated May 11, 2026

Improper locking in the Linux kernel PPP subsystem allows local users to hang the system through concurrent PPP socket activity. ppp_channel_bridge_input() takes pch->downl with spin_lock() even when socket-backlog processing can run in process context, leaving the lock interruptible by a softirq that attempts to acquire the same lock. Reachability requires low-privileged local access and traffic through the PPP channel-bridge receive path; the demonstrated consequence is a self-deadlock and service hang.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the Linux kernel PPP subsystem allows local users to hang the system through concurrent PPP socket activity. ppp_channel_bridge_input() takes pch->downl with spin_lock() even when socket-backlog processing can run in process context, leaving the lock interruptible by a softirq that attempts to acquire the same lock. Reachability requires low-privileged local access and traffic through the PPP channel-bridge receive path; the demonstrated consequence is a self-deadlock and service hang.

The record

CVE
CVE-2024-49946
Published
Oct 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record 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=4cf476ced45d7f12df30a68e833b263e7a2202d1 <176dd41e8c2bd997ed3d66568a3362e69ecce99b
  2. Affected versionversion=4cf476ced45d7f12df30a68e833b263e7a2202d1 <635deca1800a68624f185dc1e04a8495b48cf185
  3. Affected versionversion=4cf476ced45d7f12df30a68e833b263e7a2202d1 <aec7291003df78cb71fd461d7b672912bde55807
  4. Affected versionversion=4cf476ced45d7f12df30a68e833b263e7a2202d1 <c837f8583535f094a39386308c2ccfd92c8596cd
  5. Affected versionversion=4cf476ced45d7f12df30a68e833b263e7a2202d1 <efe9cc0f7c0279216a5522271ec675b8288602e4
  6. Affected versionversion=4cf476ced45d7f12df30a68e833b263e7a2202d1 <f9620e2a665aa642625bd2501282bbddff556bd7
  7. Affected versionversion=5.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4cf476ced45d7f12df30a68e833b263e7a2202d1 <176dd41e8c2bd997ed3d66568a3362e69ecce99b; version=4cf476ced45d7f12df30a68e833b263e7a2202d1 <635deca1800a68624f185dc1e04a8495b48cf185; version=4cf476ced45d7f12df30a68e833b263e7a2202d1 <aec7291003df78cb71fd461d7b672912bde55807; version=4cf476ced45d7f12df30a68e833b263e7a2202d1 <c837f8583535f094a39386308c2ccfd92c8596cd; version=4cf476ced45d7f12df30a68e833b263e7a2202d1 <efe9cc0f7c0279216a5522271ec675b8288602e4; version=4cf476ced45d7f12df30a68e833b263e7a2202d1 <f9620e2a665aa642625bd2501282bbddff556bd7; version=5.11

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Amazon LinuxCVSS: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

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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

CWE-667Improper Locking
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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