CVE-2023-26431

SSRF in Open-Xchange Appsuite Backend ≤ 7.10.6

Public PoCSSRF

Published

20 June 2023

Modified

21 November 2024

CVSS Score v3.1 5.0

Click a component to see what it means

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS Score 0.0084 57th percentile

Risk Priority 41 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-26431 is a medium-severity SSRF (CWE-918) vulnerability in Open-Xchange Open-Xchange Appsuite Backend. Its CVSS base score is 5.0 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique LSASS Memory (T1003.001); ranked in the top 43% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2023-30251

Vulnerability Data

IPv4-mapped IPv6 addresses did not get recognized as "local" by the code and a connection attempt is made. Attackers with access to user accounts could use this to bypass existing deny-list functionality and trigger requests to restricted network infrastructure to…

gain insight about topology and running services. We now respect possible IPV4-mapped IPv6 addresses when checking if contained in a deny-list. No publicly available exploits are known.

CWE(s): CWE-918

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.001 LSASS Memory Credential Access

Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).

attack.mitre.org →

T1003.005 Cached Domain Credentials Credential Access

Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.

attack.mitre.org →

T1021.001 Remote Desktop Protocol Lateral Movement

Adversaries may use [Valid Accounts](https://attack.

attack.mitre.org →

T1021.002 SMB/Windows Admin Shares Lateral Movement

Adversaries may use [Valid Accounts](https://attack.

attack.mitre.org →

T1021.004 SSH Lateral Movement

Adversaries may use [Valid Accounts](https://attack.

attack.mitre.org →

T1021.007 Cloud Services Lateral Movement

Adversaries may log into accessible cloud services within a compromised environment using [Valid Accounts](https://attack.

attack.mitre.org →

Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-26435Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26438Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26443Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26434Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26430Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26451Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26429Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26432Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26427Same product: Open-Xchange Open-Xchange Appsuite Backend

CVE-2023-26436Same product: Open-Xchange Open-Xchange Appsuite Backend

Affected Assets

open-xchange

open-xchange appsuite backend

7.10.6 · ≤ 7.10.6 · 8.0.0 — 8.11.0

Mitigating Controls

Control response

Prevent

Stop it (NIST 800-53)

—

Detect

Catch it (NIST detect / respond)

—

Harden

Shrink the surface (DISA STIG)

—

Validate

Prove the fix (OWASP ASVS)

V1.3.6
V1.5.3
V5.3.2
V10.4.7

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing

addresses: CWE-918

Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.

SC-7 Boundary Protection

addresses: CWE-918

Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.

SI-10 Information Input Validation

addresses: CWE-918

Validates server-side URLs and resource references to block SSRF attempts.

SI-4 System Monitoring

addresses: CWE-918

Detects server-side request forgery through monitoring of unexpected outbound connections.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

DE.CM-09 partial match

blocks

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match

blocks

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match

blocks

Network segmentation and egress controls can limit the damage from successful SSRF requests.

PR.PS-06 partial match

blocks

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.1 Policies for information security partial match

removes

A.5.14 Information transfer partial match

removes

A.5.15 Access control partial match

removes

A.5.16 Identity management partial match

removes

A.5.17 Authentication information partial match

removes

A.5.18 Access rights partial match

removes