CVE-2021-30185Network attack vector

Account takeover via poisoned password-reset links

Published Apr 7, 2021 · Updated Aug 3, 2024

Host header injection in CERN Indico before 2.3.4 allows remote attackers to take over user accounts via poisoned reset links. Indico's URL-generation logic trusts the request Host header when constructing emailed links, allowing an unauthenticated request to substitute an attacker-controlled hostname. Exploitation requires a recipient to click an unsolicited reset link and fails when the web server enforces a canonical hostname; success exposes the reset token and permits takeover of that Indico account.

CVSS severity7.5
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Host header injection in CERN Indico before 2.3.4 allows remote attackers to take over user accounts via poisoned reset links. Indico's URL-generation logic trusts the request Host header when constructing emailed links, allowing an unauthenticated request to substitute an attacker-controlled hostname. Exploitation requires a recipient to click an unsolicited reset link and fails when the web server enforces a canonical hostname; success exposes the reset token and permits takeover of that Indico account.

The record

CVE
CVE-2021-30185
Published
Apr 7, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-640, T1566.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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-640Weak Password Recovery Mechanism for Forgotten Password
T1566.002Phishing: Spearphishing Link

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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