CVE Intelligence
CISA KEV Low Authentication

CVE-2023-20867 — VMware Tools Authentication Bypass Vulnerability

A fully compromised ESXi host can force VMware Tools to fail to authenticate host-to-guest operations, impacting the confidentiality and integrity of the guest virtual machine.

Published Jun 13, 2023 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: vmware

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Jun 23, 2023 ☠ UNC3886
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • Exploited by 1 threat actor(s) (MITRE ATT&CK)+10
  • EPSS 13.5% (30-day exploitation probability)+14

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Jun 23, 2023
EPSS FIRST
13.53%
ahead of 96% of scored CVEs · Oct 15, 2026
Affects
Debian
Debian Linux and 2 more
CVSS base
3.9
Low · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — www.openwall.com (NIST National Vulnerability Database)
  • Documented patch — www.openwall.com (NIST National Vulnerability Database)
  • Documented patch — www.vmware.com (NIST National Vulnerability Database)

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: Jul 14, 2023 — passed 1190 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Fedoraproject Fedora, Vmware Tools).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. Apply the fixed version or the patch documented under Remediation.
  4. EPSS ahead of 96% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Debian Debian Linux version 10.0version 11.0version 12.0 Vulnerable NIST National Vulnerability Database
Fedoraproject Fedora version 37version 38version 39 Vulnerable NIST National Vulnerability Database
Vmware Tools ≥ 10.3.0 and < 12.2.5 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
High
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
3.9 CVSS 3.1 Low 0.8 2.7 security@vmware.com via NIST National Vulnerability Database
3.9 CVSS 3.1 Low 0.8 2.7 nvd@nist.gov via NIST National Vulnerability Database
3.9 CVSS 3.1 Low — — GitHub, Inc. via GitHub Security Advisories
3.9 CVSS 3.1 Low — — vmware via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-287 · Improper Authentication

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Jun 23, 2023
Federal deadline
Jul 14, 2023
passed 1190 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Threat actors exploiting this CVE MITRE ATT&CK

According to MITRE ATT&CK.

UNC3886 G1048

EPSS over time FIRST

Oct 12, 2026 → Oct 15, 2026 · 4 reading(s) · max 13.53%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
  • Hunt retroactively in logs from before Jun 23, 2023 (KEV listing): exploitation may have started earlier.
endpoint telemetry (EDR)authentication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • Affected products added · vmware/tools, debian/debian linux, fedoraproject/fedora
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 3.9
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • 2023
  • Added to CISA KEV catalog
    Jun 22, 2023 · CISA
  • CVE published
    Jun 13, 2023 · vmware

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

16 on the record

Elsewhere on this site

Debian
every CVE for this vendor
2023-06
what else CISA listed that month
Authentication
same class
CWE-287
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
  • CVE-2026-14355 ext/openssl: Memory corruption in openssl_encrypt with AES-WRAP-PAD Jul 3, 2026
  • CVE-2026-56968 Use of Uninitialized Resource in Gnu Sasl Jun 23, 2026
  • CVE-2026-54230 Abrt: event handler scripts follow symlinks when writing output files, allowing arbitrary file overwrites Jun 13, 2026
  • CVE-2026-54231 Abrt: unsanitized systemd journal content written to dump directory files enables content injection Jun 13, 2026
  • CVE-2026-49975 Apache HTTP Server: mod_http2 denial of service Jun 8, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-20867 is "VMware Tools Authentication Bypass Vulnerability", rated Low. It affects Debian Linux (Debian); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 3.9 describes technical severity. EPSS 13.53% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.