CVE-2023-45151Network attack vector

OAuth credential theft via plaintext client-secret storage

Published Oct 16, 2023 · Updated Sep 16, 2024

Cleartext storage in Nextcloud Server allows attackers with database or backup access to steal OAuth2 client secrets for linked services. The OAuth2 client registry writes each client_secret value directly to the database rather than protecting it cryptographically. Exploitation requires prior access to the live database or a database backup; exposed secrets enable OAuth2 logins to third-party services linked with the server.

CVSS severity6.5
Medium
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext storage in Nextcloud Server allows attackers with database or backup access to steal OAuth2 client secrets for linked services. The OAuth2 client registry writes each client_secret value directly to the database rather than protecting it cryptographically. Exploitation requires prior access to the live database or a database backup; exposed secrets enable OAuth2 logins to third-party services linked with the server.

The record

CVE
CVE-2023-45151
Published
Oct 16, 2023
Updated
Sep 16, 2024
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-312, CWE-313, T1555
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=>= 25.0.0, < 25.0.8
  2. Affected versionversion=>= 26.0.0, < 26.0.3
  3. Affected versionversion=>= 27.0.0, < 27.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Nextcloud GmbH · Security Advisoriesversion=>= 25.0.0, < 25.0.8; version=>= 26.0.0, < 26.0.3; version=>= 27.0.0, < 27.0.1

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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

Weakness, pattern, technique

CWE-312Cleartext Storage of Sensitive Information
CWE-313Cleartext Storage in a File or on Disk
T1555Credentials from Password Stores

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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