CVE-2021-41101Network attack vector

API access via overbroad CORS origin allowlist

Published Sep 30, 2021 · Updated Aug 4, 2024

CORS misconfiguration in nginz in Wire Server before 2.106.0 allows remote attackers to access the Wire API with a user's cookie. nginz returns Access-Control-Allow-Origin for every wire.com subdomain instead of limiting credentialed origins to applications that require the cookie. Exploitation requires script execution on an allowed subdomain and a victim with an active Wire session, exposing API data and actions available to that session.

CVSS severity5.7
Medium
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CORS misconfiguration in nginz in Wire Server before 2.106.0 allows remote attackers to access the Wire API with a user's cookie. nginz returns Access-Control-Allow-Origin for every wire.com subdomain instead of limiting credentialed origins to applications that require the cookie. Exploitation requires script execution on an allowed subdomain and a victim with an active Wire session, exposing API data and actions available to that session.

The record

CVE
CVE-2021-41101
Published
Sep 30, 2021
Updated
Aug 4, 2024
Vendor
Wire Swiss GmbH
Product
Wire Server
Classifications
CWE-79, T1550.004
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=< 2.106.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Wire Swiss GmbH · Wire Serverversion=< 2.106.0

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:P/I:N/A:N
5.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1550.004Use Alternate Authentication Material: Web Session Cookie

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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