CVE-2021-1276Network attack vector

Unauthenticated API alteration via invalid certificate acceptance

Published Jan 20, 2021 · Updated Nov 12, 2024

Cisco Data Center Network Manager before 11.5(1) allows remote attackers to alter an authentication-token API request through invalid SSL certificate acceptance. The Device Manager application fails to validate the SSL certificate when establishing its HTTPS connection, so a crafted HTTP request can modify the specific token-verification API request. The flaw requires no authentication or user interaction and affects request integrity, while Cisco reports no confidentiality or availability impact for this CVE.

CVSS severity7.5
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cisco Data Center Network Manager before 11.5(1) allows remote attackers to alter an authentication-token API request through invalid SSL certificate acceptance. The Device Manager application fails to validate the SSL certificate when establishing its HTTPS connection, so a crafted HTTP request can modify the specific token-verification API request. The flaw requires no authentication or user interaction and affects request integrity, while Cisco reports no confidentiality or availability impact for this CVE.

The record

CVE
CVE-2021-1276
Published
Jan 20, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Cisco Data Center Network Manager
Classifications
CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Data Center Network Managerversion=n/a

Published CVSS scores

7.5Cisco PSIRTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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