CVE-2016-4426Network attack vector

Bot impersonation via realm-wide API key exposure

Published Jul 28, 2022 · Updated Aug 6, 2024

Improper access control in Zulip before 1.3.12 allows remote authenticated users in the same realm to obtain other bots' API keys. Zulip's published release notes do not identify the affected endpoint or authorization check; they state only that bot API keys were exposed realm-wide. Realm membership is required, and a stolen key permits bot impersonation and access to messages the bot can read.

CVSS severity4.3
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Zulip before 1.3.12 allows remote authenticated users in the same realm to obtain other bots' API keys. Zulip's published release notes do not identify the affected endpoint or authorization check; they state only that bot API keys were exposed realm-wide. Realm membership is required, and a stolen key permits bot impersonation and access to messages the bot can read.

The record

CVE
CVE-2016-4426
Published
Jul 28, 2022
Updated
Aug 6, 2024
Vendor
Zulip
Product
Zulip
Classifications
CWE-284, T1552
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 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=zulip 1.3.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zulip · Zulipversion=zulip 1.3.12

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1552Unsecured Credentials

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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