CVE-2021-1388

highpriority · attend · 45EPSS 0.148 · 97 %ileEURUUS
grimoire priorityP1 · Urgent
Exploitable?
—
no known exploitation
Likely / severe?
14.8% (97th) EPSS
CVSS 9.3 · high
Is it mine?
5 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

A vulnerability in an API endpoint of Cisco ACI Multi-Site Orchestrator (MSO) installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. The vulnerability is due to improper token validation on a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted request to the affected API. A successful exploit could allow the attacker to receive a token with administrator-level privileges that could be used to authenticate to the API on affected MSO and managed Cisco Application Policy Infrastructure Controller (APIC) devices.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

10.0
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 9.1–10

v2.09.3highAV:N/AC:M/Au:N/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 8.6 · impact 10
v3.110criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 6
v3.110criticalAV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU
v3.110criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · ENISA EU
v3.110criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 6
v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.110criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-269USCWE-269US
05

affected products (5)

Products and version ranges known to be affected.

06

advisories (1)

Vendor and ecosystem advisories describing this.

  • cisco-sa-mso-authbyp-bb5GmBQvCisco ACI Multi-Site Orchestrator Application Services Engine Deployment Authentication Bypass Vulnerability2021-02-24csaf · cisco_csafUS

    A vulnerability in an API endpoint of Cisco ACI Multi-Site Orchestrator (MSO) installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. The vulnerability is due to improper token validation on a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted request to the affected API. A successful exploit could allow the attacker to receive a token with administrator-level privileges that could be used to authenticate to the API on affected MSO and managed Cisco Application Policy Infrastructure Controller (APIC) devices. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-mso-authbyp-bb5GmBQv ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-mso-authbyp-bb5GmBQv"]

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisco_csafnvdNVDCVE.orgMITRE
published 2021-02-24modified 2026-06-17
09

references (5)

External citations — patches, advisories, analysis.

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