CVE-2023-20900Public exploit

Privilege escalation via attacker-supplied SAML keys

Published Aug 31, 2023 · Updated Aug 2, 2024

SAML authentication bypass in VMware Tools and open-vm-tools allows attackers to perform privileged guest operations. VGAuth passes a SAML token's embedded key data to libxmlsec without restricting signature verification to trusted X.509 certificates, so a forged assertion can supply its own signing key. Exploitation requires Guest Operation Privileges and a target virtual machine mapped to a more privileged Guest Alias; successful abuse elevates guest-operation access.

CVSS severity7.1
High
EPSS probability1.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

SAML authentication bypass in VMware Tools and open-vm-tools allows attackers to perform privileged guest operations. VGAuth passes a SAML token's embedded key data to libxmlsec without restricting signature verification to trusted X.509 certificates, so a forged assertion can supply its own signing key. Exploitation requires Guest Operation Privileges and a target virtual machine mapped to a more privileged Guest Alias; successful abuse elevates guest-operation access.

The record

CVE
CVE-2023-20900
Published
Aug 31, 2023
Updated
Aug 2, 2024
Vendor
VMware
Product
VMware Tools
Classifications
CWE-294, T1606.002
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.3.x
  2. Affected versionversion=11.x.x
  3. Affected versionversion=12.x.x

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

VMware · VMware Toolsversion=10.3.x; version=11.x.x; version=12.x.x
VMware · open-vm-toolsversion=10.3.x; version=11.x.x; version=12.x.x

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.1VMwareCVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T1606.002Forge Web Credentials: SAML Tokens

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo