CVE-2026-34962Public exploit

Boot hang via zero-length ext4 directory entry

Published May 11, 2026 · Updated May 11, 2026

Infinite loop in barebox before 2026.04.0 allows attackers to halt boot by supplying a crafted ext4 filesystem image. In ext4fs_iterate_dir() in fs/ext4/ext_barebox.c, a zero direntlen is added to fpos without rejection, so iteration never advances and repeated dir_emit() allocations exhaust memory. Triggering it requires barebox to mount and traverse attacker-controlled boot media or an image delivered through a compromised update or rogue file server; the resulting panic prevents the device from booting.

CVSS severity6.9
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite loop in barebox before 2026.04.0 allows attackers to halt boot by supplying a crafted ext4 filesystem image. In ext4fs_iterate_dir() in fs/ext4/ext_barebox.c, a zero direntlen is added to fpos without rejection, so iteration never advances and repeated dir_emit() allocations exhaust memory. Triggering it requires barebox to mount and traverse attacker-controlled boot media or an image delivered through a compromised update or rogue file server; the resulting panic prevents the device from booting.

The record

CVE
CVE-2026-34962
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Pengutronix
Product
barebox
Classifications
CWE-835, T1499
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

6.9VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.2VulnCheckCVSS:3.1/AV:L/AC:L/PR:N/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.

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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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499Endpoint Denial of Service

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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