CVE-2023-25820

Password guessing via unthrottled confirmation endpoint

Published Mar 22, 2023 · Updated Feb 25, 2025

Missing brute-force protection in Nextcloud Server and Enterprise Server allows local users with a session to guess the account password. The referenced fix marks failed LostController::resetform token-validation responses for throttling, while the advisory identifies the exposed operation as password confirmation. Exploitation requires control of an already logged-in user session, and successful guessing discloses the associated account password.

CVSS severity4.2
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing brute-force protection in Nextcloud Server and Enterprise Server allows local users with a session to guess the account password. The referenced fix marks failed LostController::resetform token-validation responses for throttling, while the advisory identifies the exposed operation as password confirmation. Exploitation requires control of an already logged-in user session, and successful guessing discloses the associated account password.

The record

CVE
CVE-2023-25820
Published
Mar 22, 2023
Updated
Feb 25, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-307, T1110
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=Nextcloud Enterprise Server >= 21.0.0, < 21.0.9.10
  2. Affected versionversion=Nextcloud Enterprise Server >= 22.0.0, < 22.2.10.10
  3. Affected versionversion=Nextcloud Enterprise Server >= 23.0.0, < 23.0.12.5
  4. Affected versionversion=Nextcloud Enterprise Server >= 24.0.0, < 24.0.10
  5. Affected versionversion=Nextcloud Enterprise Server >= 25.0.0, < 25.0.4
  6. Affected versionversion=Nextcloud Server >= 24.0.0, < 24.0.10
  7. Affected versionversion=Nextcloud Server >= 25.0.0, < 25.0.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=Nextcloud Enterprise Server >= 21.0.0, < 21.0.9.10; version=Nextcloud Enterprise Server >= 22.0.0, < 22.2.10.10; version=Nextcloud Enterprise Server >= 23.0.0, < 23.0.12.5; version=Nextcloud Enterprise Server >= 24.0.0, < 24.0.10; version=Nextcloud Enterprise Server >= 25.0.0, < 25.0.4; version=Nextcloud Server >= 24.0.0, < 24.0.10; version=Nextcloud Server >= 25.0.0, < 25.0.4

Published CVSS scores

4.2NextcloudCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
T1110Brute Force

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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