CVE-2023-33184Network attack vector

Authenticated blind SSRF via unvalidated favicon host

Published May 27, 2023 · Updated Jan 14, 2025

SSRF in Nextcloud Mail before 1.15.3, 2.2.5, and 3.0.2 allows remote authenticated users to send same-host GET requests. The avatar endpoint's favicon retrieval accepts an unvalidated host and makes a server-side request to that location. A signed-in user must trigger avatar handling with user interaction; the blind response limits impact to indirect disclosure from services on the same web server.

CVSS severity3.5
Low
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Nextcloud Mail before 1.15.3, 2.2.5, and 3.0.2 allows remote authenticated users to send same-host GET requests. The avatar endpoint's favicon retrieval accepts an unvalidated host and makes a server-side request to that location. A signed-in user must trigger avatar handling with user interaction; the blind response limits impact to indirect disclosure from services on the same web server.

The record

CVE
CVE-2023-33184
Published
May 27, 2023
Updated
Jan 14, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-918
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 2025Record 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=< 1.15.3
  2. Affected versionversion=< 2.2.5
  3. Affected versionversion=< 3.02

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=< 1.15.3; version=< 2.2.5; version=< 3.02

Published CVSS scores

3.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)

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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