Cyber Resilience

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 vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
EPSS Score 0.0084 55th percentile
Risk Priority 41 floored blend · peak EPSS

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 Exploit Public-Facing Application (T1190); ranked in the top 45% 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

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…

more

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)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
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-2023-26428Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26443Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26438Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26430Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26429Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26436Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26427Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26434Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26432Same 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.

addresses: CWE-918

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

addresses: CWE-918

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

addresses: CWE-918

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

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.

PR.PS-06 mostly match
prevents

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

DE.CM-09 partial match
prevents

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

ID.RA-01 partial match
prevents

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

PR.IR-01 partial match
prevents

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

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.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

References