CVE-2026-74402 crypto: atmel-sha204a - fix blocking and non-blocking rng logic
A flaw in the Atmel SHA204A kernel driver caused weak entropy generation, potentially compromising cryptographic security for users relying on this hardware random number generator.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Not stated
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74402?
CVE-2026-74402 is a vulnerability in Linux, published on 15 Aug 2026.
Official 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
Which versions are affected by CVE-2026-74402?
How do I fix CVE-2026-74402?
Apply the vendor's patch.
Is CVE-2026-74402 being exploited?
There is no known exploitation of CVE-2026-74402 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74402, DEBIAN-CVE-2026-74402, GHSA-5f8p-9776-4575, UBUNTU-CVE-2026-74402.