Executive Summary

CVE-2026-26234 is a vulnerability in JUNG Smart Visu Server versions including 1.1.1050 that allows unauthenticated attackers to manipulate the X-Forwarded-Host HTTP request header.

By injecting arbitrary values into this header, attackers can override request URLs, causing the backend or proxy server to generate responses containing attacker-controlled hostnames.

This leads to tainted responses that can be used for cache poisoning, phishing, session hijacking, or redirecting users to malicious domains.

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Impact Analysis

This vulnerability can have serious impacts including persistent cache poisoning where malicious content is stored and served to users.

• Phishing attacks by redirecting users to malicious domains.
• Session hijacking through manipulation of responses.
• Distribution of malicious payloads via tainted cached content.

It affects confidentiality, integrity, and availability of the affected system and requires no privileges or user interaction to exploit.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'Detection of this vulnerability involves monitoring HTTP requests for manipulation of the X-Forwarded-Host header. Specifically, you should look for unusual or arbitrary values injected into this header that override request URLs.'}, {'type': 'paragraph', 'content': 'You can use network traffic inspection tools such as tcpdump or Wireshark to capture HTTP requests and filter for the X-Forwarded-Host header.'}, {'type': 'list_item', 'content': "Use tcpdump to capture HTTP traffic and filter for the X-Forwarded-Host header: tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'X-Forwarded-Host'"}, {'type': 'list_item', 'content': "Use curl to send requests with manipulated X-Forwarded-Host headers to test if the server is vulnerable: curl -H 'X-Forwarded-Host: attacker.com' http://target-server/"}, {'type': 'paragraph', 'content': 'Additionally, review server logs for requests containing suspicious X-Forwarded-Host header values that differ from expected hostnames.'}] [1, 2]

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Mitigation Strategies

Immediate mitigation steps include implementing strict validation and sanitization of the X-Forwarded-Host header on the server or proxy to prevent injection of arbitrary values.

If possible, configure the web server or proxy to ignore or overwrite the X-Forwarded-Host header with a trusted value.

Apply any available patches or updates from the vendor ALBRECHT JUNG GMBH & CO.KG once they are released.

As a temporary workaround, restrict access to the affected JUNG Smart Visu Server to trusted networks only, reducing exposure to unauthenticated attackers.

Monitor network traffic and logs for signs of exploitation attempts involving the X-Forwarded-Host header.

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