CVE-2026-23011

Kernel crash via stale GRE headroom assumptions

Published Jan 25, 2026 · Updated Jan 25, 2026

Improper buffer headroom handling in the Linux kernel allows local users to crash the kernel through an IP GRE device. mld_newpack() can allocate an skb using an outdated, undersized headroom value before ipgre_header() pushes a GRE header after device parameters change. A low-privileged local user must arrange a team or bonding device and attach an IP GRE device between allocation and transmission, causing skb_under_panic and a kernel crash.

CVSS severity5.5
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

Improper buffer headroom handling in the Linux kernel allows local users to crash the kernel through an IP GRE device. mld_newpack() can allocate an skb using an outdated, undersized headroom value before ipgre_header() pushes a GRE header after device parameters change. A low-privileged local user must arrange a team or bonding device and attach an IP GRE device between allocation and transmission, causing skb_under_panic and a kernel crash.

The record

CVE
CVE-2026-23011
Published
Jan 25, 2026
Updated
Jan 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=3.10
  2. Affected versionversion=c54419321455631079c7d6e60bc732dd0c5914c5 <554201ed0a8f4d32e719f42caeaeb2735a9ed6ca
  3. Affected versionversion=c54419321455631079c7d6e60bc732dd0c5914c5 <aa57bfea4674e6da8104fa3a37760a6f5f255dad
  4. Affected versionversion=c54419321455631079c7d6e60bc732dd0c5914c5 <e67c577d89894811ce4dcd1a9ed29d8b63476667

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.10; version=c54419321455631079c7d6e60bc732dd0c5914c5 <554201ed0a8f4d32e719f42caeaeb2735a9ed6ca; version=c54419321455631079c7d6e60bc732dd0c5914c5 <aa57bfea4674e6da8104fa3a37760a6f5f255dad; version=c54419321455631079c7d6e60bc732dd0c5914c5 <e67c577d89894811ce4dcd1a9ed29d8b63476667

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.6Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
6.6Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/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.

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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