CVE-2026-34963Public exploit

Bootloader memory corruption via EFI PE overflows

Published May 11, 2026 · Updated May 11, 2026

Memory corruption in the EFI PE loader in barebox before 2026.04.0 allows attackers to corrupt heap memory via a crafted PE binary. The loader computes virtual image sizes with overflow-prone 32-bit section arithmetic and copies sections without ensuring raw-data ranges remain inside the file buffer. Loading the binary through TFTP, USB, SD card, or network boot is required; the resulting access can crash barebox, while code execution depends on the target memory layout and allocator.

CVSS severity8.6
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in the EFI PE loader in barebox before 2026.04.0 allows attackers to corrupt heap memory via a crafted PE binary. The loader computes virtual image sizes with overflow-prone 32-bit section arithmetic and copies sections without ensuring raw-data ranges remain inside the file buffer. Loading the binary through TFTP, USB, SD card, or network boot is required; the resulting access can crash barebox, while code execution depends on the target memory layout and allocator.

The record

CVE
CVE-2026-34963
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Pengutronix
Product
barebox
Classifications
CWE-190, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2026CVE 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=0 <=2026.04.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Pengutronix · bareboxversion=0 <=2026.04.0

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.6VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.4VulnCheckCVSS:3.1/AV:L/AC:L/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1203Exploitation for Client Execution

Public exploit references

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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