CVE-2026-31616

Kernel memory corruption via unchecked skb fragments

Published Apr 24, 2026 · Updated Apr 24, 2026

Heap out-of-bounds write in the Linux kernel Phonet USB gadget function allows physically proximate attackers to corrupt kernel memory. In pn_rx_complete(), exact PAGE_SIZE transfers prevent skb finalization, so skb_add_rx_frag() increments nr_frags beyond MAX_SKB_FRAGS and writes past skb_shared_info->frags[]. The Linux system must expose the Phonet gadget function to an attacker-controlled USB host; the documented result is adjacent heap-memory corruption.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap out-of-bounds write in the Linux kernel Phonet USB gadget function allows physically proximate attackers to corrupt kernel memory. In pn_rx_complete(), exact PAGE_SIZE transfers prevent skb finalization, so skb_add_rx_frag() increments nr_frags beyond MAX_SKB_FRAGS and writes past skb_shared_info->frags[]. The Linux system must expose the Phonet gadget function to an attacker-controlled USB host; the documented result is adjacent heap-memory corruption.

The record

CVE
CVE-2026-31616
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1200
Attack vector
physical
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4e476c25bfcab0535ba7c76a903ae77ca8747711
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <66f7471c4042e4eb300e30b5b9d87d1406862673
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bd44ce09b9b569f49ed13e2d87d23d853fc7d6a7
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9315ce9da3632c591666a29de82d3e92d46bec1

What conditions does exploitation require?

Attack vectorphysical
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4e476c25bfcab0535ba7c76a903ae77ca8747711; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <66f7471c4042e4eb300e30b5b9d87d1406862673; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bd44ce09b9b569f49ed13e2d87d23d853fc7d6a7; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9315ce9da3632c591666a29de82d3e92d46bec1

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1200Hardware Additions

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo