CVE-2026-74402

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

crypto: atmel-sha204a - fix blocking and non-blocking rng logic

The blocking and non-blocking paths were failing to provide valid entropy

due to improper buffer management. Reading the buffer starting from byte 1,

only fetch the 32 bytes of random data from the return message.

Tested on an Atmel SHA204A device.

Before (here for blocking), tests showed repeatedly reading reduced bytes.

$ head -c 32 /dev/hwrng | hexdump -C

00000000 02 28 85 b3 47 40 f2 ee 00 00 00 00 00 00 00 00 |.(..G@..........|

00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|

00000020

After, the result will be similar to the following:

$ head -c 32 /dev/hwrng | hexdump -C

00000000 5a fc 3f 13 14 68 fe 06 68 0a bd 04 83 6e 09 69 |Z.?..h..h....n.i|

00000010 75 ff cf 87 10 84 3b c9 c1 df ae eb 45 53 4c c3 |u.....;.....ESL.|

00000020

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References