VulnerabilityPublished 18 Oct 2026

CVE-2026-98568: Linux kernel · vxlan: use one headroom snapshot for neighbour replies

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in ff022fd9d0f0282c575e11778b96bd1b637503eb : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in ff022fd9d0f0282c575e11778b96bd1b637503eb, a3c5eb6e382dd426a5e7eb08608897ed57167ff7, 481506a756dcd828ef42391cb08f38d8d96d38fc +4

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=3.12.18 <3.13 >=3.13.10 <3.14	Fixed in ff022fd9d0f0282c575e11778b96bd1b637503eb a3c5eb6e382dd426a5e7eb08608897ed57167ff7 481506a756dcd828ef42391cb08f38d8d96d38fc 315d42ca39f69846662961c25dcf2bb07c350d14 45a67662bf8ce3aa5643accf98d328dfbb47eaf6 3.14 3.13
LinuxLinux	Affected =3.14	Fixed in–

AI-suggested

A fix is available in Linux kernel versions 3.13 and 3.14 and later. Users should upgrade to these or newer versions to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.

Description

A race condition vulnerability in the Linux kernel's VXLAN implementation could cause out-of-bounds writes when generating neighbor replies. The flaw arises from inconsistent headroom size sampling during packet allocation and reservation, leading to potential memory corruption. This issue affects certain Linux kernel versions prior to 3.14 and has been fixed in versions 3.13 and 3.14.

Impact

This vulnerability can cause out-of-bounds memory writes in the kernel, potentially leading to memory corruption or system instability. However, there is no indication of known exploitation in the wild. The impact is limited to affected Linux kernel versions handling VXLAN neighbor replies concurrently with link changes.

Summary

The Linux kernel's vxlan_na_create() function samples LL_RESERVED_SPACE() twice to size and reserve headroom for neighbor replies. A concurrent vxlan_changelink() call can update the needed_headroom value between these two reads, causing a time-of-check to time-of-use (TOCTOU) race condition. This race can result in the second headroom value exceeding the allocated buffer size, leading to an out-of-bounds write in the Ethernet header. The vulnerability was detected by KASAN during a four-byte write beyond the allocated skbuff_small_head buffer. The fix involves taking a single snapshot of the headroom value and using it consistently for allocation and reservation.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 10:37 UTC

Technical details

References

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