CVE-2022-49907

Boot-time UBSAN warning via signed bit shift

Published May 1, 2025 · Updated May 11, 2026

Undefined behavior in Linux kernel branches from 2.6.28 through 6.0.7 triggers a UBSAN warning during MDIO bus initialization. __mdiobus_register in drivers/net/phy/mdio_bus.c evaluates 1 << 31 as a signed int while constructing the PHY mask, an operation C leaves undefined. The path runs only during fixed MDIO bus boot initialization; Ubuntu reports that attackers cannot invoke or influence it and that it has no practical security impact on supported architectures.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Undefined behavior in Linux kernel branches from 2.6.28 through 6.0.7 triggers a UBSAN warning during MDIO bus initialization. __mdiobus_register in drivers/net/phy/mdio_bus.c evaluates 1 << 31 as a signed int while constructing the PHY mask, an operation C leaves undefined. The path runs only during fixed MDIO bus boot initialization; Ubuntu reports that attackers cannot invoke or influence it and that it has no practical security impact on supported architectures.

The record

CVE
CVE-2022-49907
Published
May 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. May 1, 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

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Is a vulnerable build present?

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

  1. Affected versionversion=2.6.28
  2. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <20ed01a7b9af6e6a3c33761eebbb710ea6dd49b7
  3. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <40e4eb324c59e11fcb927aa46742d28aba6ecb8a
  4. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <4954b5359eb141499492fadfab891e28905509e2
  5. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <634f066d02bdb22a26da7deb0c7617ab1a65fc9d
  6. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <6ce6f8f8f6316da6f92afe7490bc2f0b654d68e0
  7. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <7006176a3c863e3e353ce1b8a349ef5bb1b9320e
  8. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <985a88bf0b27193522bba7856b1763f428cef19d
  9. Affected versionversion=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <a3fafc974be37319679f36dc4e7cca7db1e02973

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.28; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <20ed01a7b9af6e6a3c33761eebbb710ea6dd49b7; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <40e4eb324c59e11fcb927aa46742d28aba6ecb8a; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <4954b5359eb141499492fadfab891e28905509e2; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <634f066d02bdb22a26da7deb0c7617ab1a65fc9d; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <6ce6f8f8f6316da6f92afe7490bc2f0b654d68e0; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <7006176a3c863e3e353ce1b8a349ef5bb1b9320e; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <985a88bf0b27193522bba7856b1763f428cef19d; version=4fd5f812c23c7deee6425f4a318e85c317cd1d6c <a3fafc974be37319679f36dc4e7cca7db1e02973

Published CVSS scores

7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Amazon LinuxCVSS: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

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
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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