CVE-2023-26438Network attack vector

Restricted-service discovery via DNS cache race

Published Aug 2, 2023 · Updated Aug 2, 2024

SSRF in OX App Suite backend 7.10.6-rev42 and earlier and 8.10 and earlier allows remote authenticated users to probe restricted services. The external-service lookup checks a hostname against network deny-lists, then uses it after the JDK DNS cache can expire, allowing a rebound address to bypass the prior check. Exploitation requires an authenticated user to time DNS cache expiry; it discloses only the existence and availability of restricted network services.

CVSS severity4.3
Medium
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in OX App Suite backend 7.10.6-rev42 and earlier and 8.10 and earlier allows remote authenticated users to probe restricted services. The external-service lookup checks a hostname against network deny-lists, then uses it after the JDK DNS cache can expire, allowing a rebound address to bypass the prior check. Exploitation requires an authenticated user to time DNS cache expiry; it discloses only the existence and availability of restricted network services.

The record

CVE
CVE-2023-26438
Published
Aug 2, 2023
Updated
Aug 2, 2024
Vendor
Open-Xchange GmbH
Product
OX App Suite
Classifications
CWE-918, CWE-367, T1046
Attack vector
network
Privileges
authenticated

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 <=7.10.6-rev42
  2. Affected versionversion=0 <=8.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Open-Xchange GmbH · OX App Suiteversion=0 <=7.10.6-rev42; version=0 <=8.10

Published CVSS scores

4.3Open-Xchange GmbHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
3.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/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.

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)
CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1046Network Service Discovery

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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