CVE-2026-98393Hinoki check available

Kernel warning via unchecked UDP length

Published Oct 14, 2026 · Updated Oct 14, 2026

UDP length overflow in Linux IPv4 output allows local users to trigger a kernel warning by sending an oversized UDP datagram. In net/ipv4/ip_output.c, ip_setup_cork accepts an oversized device MTU without clamping the packet size, allowing the UDP length to overflow its 16-bit field. Triggering requires probe-mode path MTU discovery and an unusually large interface MTU; the disclosed consequence is a warning in udp_set_len_short, not a demonstrated crash or privilege escalation.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

UDP length overflow in Linux IPv4 output allows local users to trigger a kernel warning by sending an oversized UDP datagram. In net/ipv4/ip_output.c, ip_setup_cork accepts an oversized device MTU without clamping the packet size, allowing the UDP length to overflow its 16-bit field. Triggering requires probe-mode path MTU discovery and an unusually large interface MTU; the disclosed consequence is a warning in udp_set_len_short, not a demonstrated crash or privilege escalation.

The record

CVE
CVE-2026-98393
Published
Oct 14, 2026
Updated
Oct 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 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=3.13
  2. Affected versionversion=daba287b299ec7a2c61ae3a714920e90e8396ad5 <81f540827d243b8dad76c1f44e70ea31719f393c
  3. Affected versionversion=daba287b299ec7a2c61ae3a714920e90e8396ad5 <83fedc4741210f75be8ca5b487985a242bf6f18d
  4. Affected versionversion=daba287b299ec7a2c61ae3a714920e90e8396ad5 <b83641e0ab8b20eefcc4cdc5a059f897375291a2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=3.13; version=daba287b299ec7a2c61ae3a714920e90e8396ad5 <81f540827d243b8dad76c1f44e70ea31719f393c; version=daba287b299ec7a2c61ae3a714920e90e8396ad5 <83fedc4741210f75be8ca5b487985a242bf6f18d; version=daba287b299ec7a2c61ae3a714920e90e8396ad5 <b83641e0ab8b20eefcc4cdc5a059f897375291a2

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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