CVE-2026-23254

Network interruption via incorrect UDP GRO offset

Published Mar 18, 2026 · Updated Mar 18, 2026

Improper packet handling in affected Linux Kernel releases allows local users to interrupt UDP processing via crafted GSO traffic. At UDP GRO completion, udp4_gro_complete() trusts an uncleared encapsulation flag and uses an inner-network offset to calculate the outer UDP pseudo-header checksum. Reachability requires locally injecting UDP-encapsulated GSO packets through tun or veth, or traffic from a NIC that sets the flag; the result is checksum-validation failure and packet-processing interruption.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper packet handling in affected Linux Kernel releases allows local users to interrupt UDP processing via crafted GSO traffic. At UDP GRO completion, udp4_gro_complete() trusts an uncleared encapsulation flag and uses an inner-network offset to calculate the outer UDP pseudo-header checksum. Reachability requires locally injecting UDP-encapsulated GSO packets through tun or veth, or traffic from a NIC that sets the flag; the result is checksum-validation failure and packet-processing interruption.

The record

CVE
CVE-2026-23254
Published
Mar 18, 2026
Updated
Mar 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 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=5ef31ea5d053a8f493a772ebad3f3ce82c35d845 <2e5edb69e5d0e23ef248c56fc977039268c77a7b
  2. Affected versionversion=5ef31ea5d053a8f493a772ebad3f3ce82c35d845 <5c2c3c38be396257a6a2e55bd601a12bb9781507
  3. Affected versionversion=5ef31ea5d053a8f493a772ebad3f3ce82c35d845 <b83557bc6f560433fe5d727e241069f8db5ba709
  4. Affected versionversion=6.9
  5. Affected versionversion=af276a5ac8e938c8b058e3e124073cc1e322d98b <9d40a85138568696387ef04cd004c64612a70874
  6. Affected versionversion=dbd9466d323a72e22efe09151253d195d36d3bf6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5ef31ea5d053a8f493a772ebad3f3ce82c35d845 <2e5edb69e5d0e23ef248c56fc977039268c77a7b; version=5ef31ea5d053a8f493a772ebad3f3ce82c35d845 <5c2c3c38be396257a6a2e55bd601a12bb9781507; version=5ef31ea5d053a8f493a772ebad3f3ce82c35d845 <b83557bc6f560433fe5d727e241069f8db5ba709; version=6.9; version=af276a5ac8e938c8b058e3e124073cc1e322d98b <9d40a85138568696387ef04cd004c64612a70874; version=dbd9466d323a72e22efe09151253d195d36d3bf6

Published CVSS scores

5.5NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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