CVE-2026-80922

What it actually does

The qcom-rng driver in the Linux kernel previously rejected zero as a valid random output, resulting in a biased random number generator whose outputs were statistically distinguishable from true randomness.

Why it matters to the business

Cryptographic operations relying on this hardware RNG could experience reduced entropy, raising the risk of weakened encryption, key generation, or other security mechanisms across affected Linux systems.

How an attack unfolds

An attacker capable of observing repeated outputs from the affected RNG performs statistical analysis to detect the absence of zero values, then leverages the resulting bias to improve guesses or attacks against dependent cryptographic functions.

How to fix it

Update the Linux kernel to a version containing the qcom-rng change that permits zero as a valid random value.

How to confirm the fix worked

Inspect the qcom-rng driver source to confirm zero is accepted, or run statistical randomness tests on large sample sets to verify uniform distribution including zero.

Typical attack path

1. Obtain repeated samples from the qcom-rng hardware interface
2. Apply statistical tests to confirm bias against zero outputs
3. Use the reduced entropy to mount cryptanalysis against keys or nonces derived from the RNG

How to detect it

Examine kernel boot logs and RNG initialization messages for references to qcom-rng; review cryptographic library behavior for any observable bias patterns in generated values.

What your security team should do

• Apply the kernel update that resolves the RNG bias as soon as packages are available
• Audit any applications or libraries that directly consume qcom-rng output for cryptographic use
• Fallback to alternative kernel RNG sources such as /dev/urandom where hardware-specific drivers are not required