CVE-2025-38622

Local crash via undersized UDP UFO segments

Published Aug 22, 2025 · Updated May 11, 2026

Improper UDP segmentation in affected Linux kernel releases allows local users to crash the system through crafted TUN packets. udp_rcv_segment accepts UFO traffic even though receive-path segmentation was intended only for GRO, leaving udp_csum_pull_header to pull a UDP header from an undersized segment. Triggering the crash requires a virtio-net header with SKB_GSO_UDP, a GSO size below the UDP-header size, and UDP_ENCAP_ESPINUDP; no data disclosure or modification is reported.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper UDP segmentation in affected Linux kernel releases allows local users to crash the system through crafted TUN packets. udp_rcv_segment accepts UFO traffic even though receive-path segmentation was intended only for GRO, leaving udp_csum_pull_header to pull a UDP header from an undersized segment. Triggering the crash requires a virtio-net header with SKB_GSO_UDP, a GSO size below the UDP-header size, and UDP_ENCAP_ESPINUDP; no data disclosure or modification is reported.

The record

CVE
CVE-2025-38622
Published
Aug 22, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=5.0
  2. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <0c639c6479ec4480372901a5fc566f7588cf5522
  3. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <0d45954034f8edd6d4052e0190d3d6335c37e4de
  4. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <4c1022220b1b6fea802175e80444923a3bbf93a5
  5. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <72f97d3cb791e26492236b2be7fd70d2c6222555
  6. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <791f32c5eab33ca3a153f8f6f763aa0df1ddc320
  7. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <c0ec2e47f1e92d69b42b17a4a1e543256778393e
  8. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <d46e51f1c78b9ab9323610feb14238d06d46d519
  9. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <df6ad849d59256dcc0e2234844ef9f0daf885f5c
  10. Affected versionversion=cf329aa42b6659204fee865bbce0ea20462552eb <fc45b3f9599b657d4a64bcf423d2a977b3e13a49

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.0; version=cf329aa42b6659204fee865bbce0ea20462552eb <0c639c6479ec4480372901a5fc566f7588cf5522; version=cf329aa42b6659204fee865bbce0ea20462552eb <0d45954034f8edd6d4052e0190d3d6335c37e4de; version=cf329aa42b6659204fee865bbce0ea20462552eb <4c1022220b1b6fea802175e80444923a3bbf93a5; version=cf329aa42b6659204fee865bbce0ea20462552eb <72f97d3cb791e26492236b2be7fd70d2c6222555; version=cf329aa42b6659204fee865bbce0ea20462552eb <791f32c5eab33ca3a153f8f6f763aa0df1ddc320; version=cf329aa42b6659204fee865bbce0ea20462552eb <c0ec2e47f1e92d69b42b17a4a1e543256778393e; version=cf329aa42b6659204fee865bbce0ea20462552eb <d46e51f1c78b9ab9323610feb14238d06d46d519; version=cf329aa42b6659204fee865bbce0ea20462552eb <df6ad849d59256dcc0e2234844ef9f0daf885f5c; version=cf329aa42b6659204fee865bbce0ea20462552eb <fc45b3f9599b657d4a64bcf423d2a977b3e13a49

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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

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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Your stack

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