OpsTree REMS: Prompt injection in RCA chat assistant discloses system prompt
Summary
OpsTree REMS through version 1.0.0 contains a prompt injection vulnerability in the RCA chat assistant at POST /api/v1/rca/chat. An authenticated user can submit crafted chat input that makes the assistant reveal its hidden system prompt and internal orchestration instructions. The leak does not directly expose business data, but it makes further prompt injection attacks easier.
Affected
- OpsTree REMS 0 to 1.0.0 (inclusive), per the CNA record
Fixed in
Unknown. The researcher's advisory states that OpsTree has fixed the issue, but no fixed version number is published.
Workaround
Unknown. No vendor workaround is published.
- Restrict user accounts to those that are needed.
- Keep REMS off the internet.
- Log use of the chat endpoint.
Exploitation
- Not known to be exploited in the wild.
- VulDB reports that technical details are known, but no public exploit is confirmed by the sources reviewed.
- Authentication is required.
Our recommendation
- Ask OpsTree Solutions for a fixed version and install it as soon as it is available.
- Keep REMS in internal networks only and restrict accounts to necessary users.
- Log and review requests to POST /api/v1/rca/chat.
- Check whether REMS is used in your environment.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE Record CVE-2026-126767 www.cve.org
- VulnCheck advisory: OpsTree REMS prompt injection via RCA chat assistant www.vulncheck.com
- Researcher advisory (GitHub gist) gist.github.com
- VulDB entry CVE-2026-126767 vuldb.com
- OffSeq Radar: CVE-2026-126767 radar.offseq.com
- OpsTree REMS product page opstree.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 20:45.
Original description (NVD)
OpsTree REMS through 1.0.0 contains a prompt injection vulnerability that allows authenticated users to disclose the hidden system prompt by submitting crafted chat input to POST /api/v1/rca/chat. Attackers can instruct the assistant to ignore its rules and reveal internal orchestration instructions, aiding the crafting of further prompt injection attacks.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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