CVE-2023-25161Network attack vector

Service degradation via unthrottled password-reset emails

Published Feb 13, 2023 · Updated Mar 10, 2025

Improper access control in Nextcloud Server before 23.0.12, 24.0.8, or 25.0.1 allows remote attackers to degrade service. LostController processed each public password-recovery request by sending email without a per-user limit; the patch registers a five-message limit over 30 minutes before generating another reset token. The endpoint requires no authentication, and repeated requests can slow the service, consume storage, or incur charges from an external email provider.

CVSS severity3.7
Low
EPSS probability0.73%
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 Nextcloud Server before 23.0.12, 24.0.8, or 25.0.1 allows remote attackers to degrade service. LostController processed each public password-recovery request by sending email without a per-user limit; the patch registers a five-message limit over 30 minutes before generating another reset token. The endpoint requires no authentication, and repeated requests can slow the service, consume storage, or incur charges from an external email provider.

The record

CVE
CVE-2023-25161
Published
Feb 13, 2023
Updated
Mar 10, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-284, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 13, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 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=< 23.0.2
  2. Affected versionversion=>= 24.0.0, < 24.0.8
  3. Affected versionversion== 25.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=< 23.0.2; version=>= 24.0.0, < 24.0.8; version== 25.0.0

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
3.7GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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