CVE-2026-74402

Reduced hardware entropy via response-buffer misalignment

Published Aug 15, 2026 · Updated Aug 15, 2026

Insufficient entropy in the Atmel SHA204A driver in affected Linux kernels allows local users to receive reduced random data via /dev/hwrng. The blocking and non-blocking RNG paths copy the response from the wrong buffer offset instead of skipping byte zero and returning only the 32-byte payload. Exposure requires an Atmel SHA204A device bound to the driver; the result weakens hardware-supplied entropy, with no published demonstration of direct secret recovery.

CVSS severity4.0
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

Insufficient entropy in the Atmel SHA204A driver in affected Linux kernels allows local users to receive reduced random data via /dev/hwrng. The blocking and non-blocking RNG paths copy the response from the wrong buffer offset instead of skipping byte zero and returning only the 32-byte payload. Exposure requires an Atmel SHA204A device bound to the driver; the result weakens hardware-supplied entropy, with no published demonstration of direct secret recovery.

The record

CVE
CVE-2026-74402
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-331
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=5.3
  2. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <2fa302bbc62dec7cb6339c9494e0e3f2f884afeb
  3. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <319400fc5ee15db5793aa45f854968141326effc
  4. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <76269a91fd9560c5f03c3e59421a0329e39a6661
  5. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <9039bb4f238474379221fc933c34f19f0cba501b
  6. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <938ae1fb4a8f5db43b62b6206d409efbf317f0d9
  7. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <aac63bbea8fd5a34f1a4305cb73369068f952d32
  8. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <d4aa6141ff03ec82eed6fcef814300fb855ce5d8
  9. Affected versionversion=da001fb651b00e1deeaf24767dd691ae8152a4f5 <e833e865e4944ba75120db534bd931db6cf677d3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.3; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <2fa302bbc62dec7cb6339c9494e0e3f2f884afeb; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <319400fc5ee15db5793aa45f854968141326effc; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <76269a91fd9560c5f03c3e59421a0329e39a6661; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <9039bb4f238474379221fc933c34f19f0cba501b; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <938ae1fb4a8f5db43b62b6206d409efbf317f0d9; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <aac63bbea8fd5a34f1a4305cb73369068f952d32; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <d4aa6141ff03ec82eed6fcef814300fb855ce5d8; version=da001fb651b00e1deeaf24767dd691ae8152a4f5 <e833e865e4944ba75120db534bd931db6cf677d3

Published CVSS scores

4.0Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy

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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