CVE Intelligence
High Authentication

CVE-2023-20900 — Authentication Bypass by Capture-replay in Debian Debian Linux

A malicious actor that has been granted Guest Operation Privileges https://docs.vmware.com/en/VMware-vSphere/8.0/vsphere-security/GUID-6A952214-0E5E-4CCF-9D2A-90948FF643EC.html  in a target virtual machine may be able to elevate their privileges if that target virtual machine has been assigned a more privileged Guest Alias https://vdc-download.vmware.com/vmwb-repository/dcr-public/d1902b0e-d479-46bf-8ac9-cee0e31e8ec0/07ce8dbd-db48-4261-9b8f-c6d3ad8ba472/vim.vm.guest.AliasManager.html .

Published Aug 31, 2023 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · 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.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 1.5% (30-day exploitation probability)+11
  • Technical severity (high)+6

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
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
1.46%
ahead of 73% of scored CVEs · Oct 14, 2026
Affects
Debian
Debian Linux and 4 more
CVSS base
7.5
High · 3 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
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
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.vmware.com (NIST National Vulnerability Database)

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, Netapp Ontap Select Deploy Administration Utility…).
  2. Apply the fixed version or the patch documented under Remediation.
  3. 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
Netapp Ontap Select Deploy Administration Utility versions not specified by the source Vulnerable NIST National Vulnerability Database
Vmware Open Vm Tools ≥ 10.3.0 and < 12.3.0 Vulnerable NIST National Vulnerability Database
Vmware Tools ≥ 10.3.0 and < 12.3.0≥ 10.3.0 and < 10.3.26 Vulnerable NIST National Vulnerability Database

Attack characteristics

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

Attack vector
Adjacent
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 1.6 5.9 nvd@nist.gov via NIST National Vulnerability Database
7.1 CVSS 3.1 High 1.2 5.9 security@vmware.com via NIST National Vulnerability Database
7.1 CVSS 3.1 High — — vmware via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)
Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 7.5 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-294 · Authentication Bypass by Capture-replay

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 1.46%

Detection

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

  • Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
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
  • CVSS changed · 7.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2023
  • CVE published
    Aug 31, 2023 · vmware

Source activity

Repeated readings are counted rather than listed.

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

References

9 on the record

Elsewhere on this site

Debian
every CVE for this vendor
Authentication
same class
CWE-294
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-2026-54231 Abrt: unsanitized systemd journal content written to dump directory files enables content injection Jun 13, 2026
  • CVE-2026-54230 Abrt: event handler scripts follow symlinks when writing output files, allowing arbitrary file overwrites 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-2023-20900 is "Authentication Bypass by Capture-replay in Debian Debian Linux", rated High. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 1.46% 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.