CVE intelligence and bounded remediation

CVE-2023-26436 — Open-Xchange Open-Xchange Appsuite Backend security vulnerability

High CVSS 8.8

Attackers with access to the "documentconverterws" API were able to inject serialized Java objects, that were not properly checked during deserialization. Access to this API endpoint is restricted to local networks by default. Arbitrary code could be injected that is being executed when processing the request. A check has been introduced to restrict processing of legal and expected classes for this API. We now log a warning in case there are attempts to inject illegal classes. No publicly available exploits are known.

Severity
High
CVSS
8.8 (3.1)
Published
2023-06-20
CISA KEV
Not currently listed
Ecosystem
java/maven
Weaknesses
CWE-94, CWE-502

Affected products

  • open-xchange / open-xchange_appsuite_backend
  • open-xchange / open-xchange_appsuite_backend / 7.10.6

Showing 2 representative product identities from 3 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

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Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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