CVE-2026-74543

Local denial of service via unreleased tunnel allocations

Published Aug 15, 2026 · Updated Aug 15, 2026

Resource leak in the Linux kernel UDP tunnel NIC offload code allows local users to exhaust memory by causing device registration failures. udp_tunnel_nic_unregister() returns early when work is pending, so failed registration receives no later unregister notification and permanently leaks its udp_tunnel_nic allocation. Local low-privileged access and queued NETDEV_REGISTER work are required; repeated triggers consume kernel memory and can interrupt service.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leak in the Linux kernel UDP tunnel NIC offload code allows local users to exhaust memory by causing device registration failures. udp_tunnel_nic_unregister() returns early when work is pending, so failed registration receives no later unregister notification and permanently leaks its udp_tunnel_nic allocation. Local low-privileged access and queued NETDEV_REGISTER work are required; repeated triggers consume kernel memory and can interrupt service.

The record

CVE
CVE-2026-74543
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-772, CWE-401, T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=5.9
  2. Affected versionversion=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <080695e6f005e2396f1207fd69d24c442cb230c6
  3. Affected versionversion=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <b322532a4b774db1b480a2de84125910a70739a5
  4. Affected versionversion=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <b712da45bd9b9835d132e9fbc0c3e43c164cb1fd
  5. Affected versionversion=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <f82a2ded3d7a9098267c84f14eafdb98c4550ac5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.9; version=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <080695e6f005e2396f1207fd69d24c442cb230c6; version=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <b322532a4b774db1b480a2de84125910a70739a5; version=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <b712da45bd9b9835d132e9fbc0c3e43c164cb1fd; version=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <f82a2ded3d7a9098267c84f14eafdb98c4550ac5

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.5Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

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

CWE-772Missing Release of Resource after Effective Lifetime
CWE-401Missing Release of Memory after Effective Lifetime
T1499.001OS Exhaustion Flood

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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