Bug 2516892 (CVE-2026-74438)

Summary: CVE-2026-74438 kernel: crypto: sun4i-ss - Remove insecure and unused rng_alg
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's sun4i-ss cryptographic random number generator (RNG). This component contains multiple vulnerabilities, including a buffer overflow in the sun4i_ss_prng_seed() function that could lead to a denial of service. Furthermore, the sun4i_ss_prng_generate() function may not generate a full complement of cryptographic random bytes, potentially weakening security where this specific RNG is theoretically used. Although this code is not known to be actively utilized, these underlying issues pose a security risk.
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Description OSIDB Bzimport 2026-08-15 06:38:57 UTC 
In the Linux kernel, the following vulnerability has been resolved:

crypto: sun4i-ss - Remove insecure and unused rng_alg

Remove sun4i_ss_rng, as it is insecure and unused:

- It has multiple vulnerabilities.  sun4i_ss_prng_seed() is missing
  locking and has a buffer overflow.  sun4i_ss_prng_generate() fails to
  fill the entire buffer with cryptographic random bytes, because it
  rounds the destination length down and also doesn't actually wait for
  the hardware to be ready before pulling bytes from it.

- No user of this code is known.  It's usable only theoretically via the
  "rng" algorithm type of AF_ALG.  But userspace actually just uses the
  actual Linux RNG (/dev/random etc) instead.  And rng_algs don't
  contribute entropy to the actual Linux RNG either.  (This may have
  been confused with hwrng, which does contribute entropy.)

The sun4i_ss_prng_seed() buffer overflow was reported by Tianchu Chen
and discovered by Atuin - Automated Vulnerability Discovery Engine

There's no point in fixing all these vulnerabilities individually when
this is unused code, so let's just remove it.
Comment 1 Keith Grant 2026-08-20 23:21:33 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081516-CVE-2026-74438-d66c@gregkh/T