CVE-2023-26451Network attack vector

Account takeover via predictable OAuth authorization codes

Published Aug 2, 2023 · Updated Aug 2, 2024

Weak authorization-code generation in OX App Suite backend 8.11 allows remote attackers to take over OAuth sessions via predicted codes. The integrated OAuth Authorization Service generates authorization codes with a source that lacks sufficient randomness, making the one-time codes predictable. The service is disabled by default; exposure requires the internal OAuth authorization server to be enabled, after which a predicted code can compromise another user's account.

CVSS severity7.5
High
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak authorization-code generation in OX App Suite backend 8.11 allows remote attackers to take over OAuth sessions via predicted codes. The integrated OAuth Authorization Service generates authorization codes with a source that lacks sufficient randomness, making the one-time codes predictable. The service is disabled by default; exposure requires the internal OAuth authorization server to be enabled, after which a predicted code can compromise another user's account.

The record

CVE
CVE-2023-26451
Published
Aug 2, 2023
Updated
Aug 2, 2024
Vendor
Open-Xchange GmbH
Product
OX App Suite
Classifications
CWE-330, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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=0 <=8.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Open-Xchange GmbH · OX App Suiteversion=0 <=8.11

Published CVSS scores

7.5Open-Xchange GmbHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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.

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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-330Use of Insufficiently Random Values
T1528Steal Application Access Token

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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