VulnerabilityPublished 23 Oct 2026

CVE-2026-98954: Linux kernel · net: always dissect GSO packets in __virtio_net_hdr_to_skb()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in 44378d02c5aaae24b60a75fbbb539b4aa4db503d : patch Linux kernel soon.

Data as of 26 Oct 2026, 15:35 UTC

Severity

High

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 44378d02c5aaae24b60a75fbbb539b4aa4db503d, 5f4dfdf0077730e9d3ef5b37ceb17a5a56d6f34c, 4.21 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 23 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 >=4.14.104 <4.15 >=4.19.26 <4.20 >=4.20.13 <4.21 >=4.14.226 <4.15 >=4.19.181 <4.20	Fixed in 44378d02c5aaae24b60a75fbbb539b4aa4db503d 5f4dfdf0077730e9d3ef5b37ceb17a5a56d6f34c 4.21 4.20 4.15
LinuxLinux	Affected =5.0	Fixed in–

AI-suggested

A fix is available and has been applied in Linux kernel versions 4.15, 4.20, 4.21, and later. Users and administrators should upgrade affected Linux kernel versions to these fixed releases or later to remediate the vulnerability. No additional mitigation actions are indicated by the vendor advisory.

Description

CVE-2026-98954 is a vulnerability in the Linux kernel's network stack related to improper handling of Generic Segmentation Offload (GSO) packets in the __virtio_net_hdr_to_skb() function. The flaw involves incorrect flow dissection and validation of GSO packets, which can lead to out-of-bounds memory reads when processing malformed or specially crafted network packets. This issue has been fixed in Linux kernel versions 4.15, 4.20, and 4.21 and later.

Impact

This vulnerability can cause kernel memory out-of-bounds reads leading to kernel crashes or potential denial of service. It affects packet processing in the network stack, specifically when handling GSO packets with malformed network headers or packets with IP options or IPv6 extension headers. There is no indication of confirmed exploitation in the wild or direct code execution impact from the provided data.

Summary

The vulnerability arises because __virtio_net_hdr_to_skb() improperly skips flow dissection of GSO packets when skb->network_header is zero, which is a valid offset but was treated as a boolean false. This leads to incomplete validation and failure to set skb->transport_header, causing subsequent functions like skb_gso_transport_seglen() to read out-of-bounds memory. The problem affects several callers that invoke virtio_net_hdr_*_to_skb() before initializing skb->network_header and skb->dev. The fix involves initializing these fields properly before the call, removing the flawed conditional check, and ensuring full flow dissection and validation of GSO packets without the VIRTIO_NET_HDR_F_NEEDS_CSUM flag. Additionally, protocol validation was moved to a more appropriate location to avoid skipping checks for VLAN-tagged frames.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 15:35 UTC

Technical details

References

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