CVE-2026-23751
Published: 23 April 2026
Description
Kofax Capture, now referred to as Tungsten Capture, version 6.0.0.0 (other versions may be affected) exposes a deprecated .NET Remoting HTTP channel on port 2424 via the Ascent Capture Service that is accessible without authentication and uses a default, publicly…
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known endpoint identifier. An unauthenticated remote attacker can exploit .NET Remoting object unmarshalling techniques to instantiate a remote System.Net.WebClient object and read arbitrary files from the server filesystem, write attacker-controlled files to the server, or coerce NTLMv2 authentication to an attacker-controlled host, enabling sensitive credential disclosure, denial of service, remote code execution, or lateral movement depending on service account privileges and network environment.
Mitigating Controls (NIST 800-53 r5)AI
Restricting systems to least functionality eliminates the unnecessary deprecated .NET Remoting channel on port 2424, preventing unauthenticated remote exploitation.
Boundary protection controls network communications to block unauthorized inbound access to the exposed unauthenticated HTTP channel on port 2424.
Limits permitted actions without identification or authentication, directly prohibiting unauthenticated access to critical Remoting functions enabling file operations and code execution.
Security SummaryAI
CVE-2026-23751 affects Kofax Capture, now referred to as Tungsten Capture, specifically version 6.0.0.0, with other versions potentially vulnerable. The vulnerability stems from the Ascent Capture Service exposing a deprecated .NET Remoting HTTP channel on port 2424, which is accessible without authentication and uses a default, publicly known endpoint identifier. This misconfiguration enables exploitation through .NET Remoting object unmarshalling techniques, as scored at CVSS 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) and linked to CWEs-306 (Missing Authentication for Critical Function) and CWE-441 (Unintended Proxy or Intermediary).
An unauthenticated remote attacker can exploit this by instantiating a remote System.Net.WebClient object via the exposed channel. This allows reading arbitrary files from the server filesystem, writing attacker-controlled files to the server, or coercing NTLMv2 authentication to an attacker-controlled host. Depending on the privileges of the service account and the network environment, successful exploitation can lead to sensitive credential disclosure, denial of service, remote code execution, or lateral movement.
Advisories and resources, including the Tungsten Automation documentation, a GitHub gist detailing the issue, and a VulnCheck advisory, provide additional technical details on the vulnerability, such as proof-of-concept exploitation steps for file read/write and SMB coercion via .NET Remoting. Practitioners should consult these for guidance on identification and potential workarounds, as no specific patch details are outlined in the core CVE information.
Details
- CWE(s)
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
T1190 for unauthenticated exploitation of public-facing .NET Remoting service; T1005 for arbitrary file reads; T1105 for writing attacker-controlled files; T1187 for NTLMv2 authentication coercion.