# CVE-2026-126767: OpsTree REMS through 1.0.0 Prompt Injection via RCA Chat Assistant

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- OpsTree Solutions / REMS: ≥ 0; ≤ 1.0.0 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-1427

## Exploit evidence

- exploit: https://gist.github.com/neelkotnis/548bfde3e45bc3793f3f26e1f9a43efe (CNA: VulnCheck)

## References

- https://gist.github.com/neelkotnis/548bfde3e45bc3793f3f26e1f9a43efe (CNA: VulnCheck; technical-description, exploit)

- https://opstree.com/rems-ai-powered-observability/ (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/opstree-rems-through-1.0.0-prompt-injection-via-rca-chat-assistant (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126767; retrieved 2026-11-11; source updated 2026-11-11

Revision: 7550f0797e37b47592412664fe93fa90345abca4bcc23f8287ece5be6b16ebf7

Canonical: https://y2.dev/cve/CVE-2026-126767

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.