---
id: "CVE-2026-126771"
page: "https://infrastack.ai/live/CVE-2026-126771"
kind: "vulnerability"
aliases: ["CVE-2026-126771"]
title: "OpsTree REMS: uploaded attachments run scripts in other users' browsers"
severity: "medium"
cvss: 5.4
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["opstree-rems", "other", "self-hosted"]
not_affected_if: ["no-attachment-uploads"]
published_at: "2026-11-11T19:17:37+00:00"
first_seen_at: "2026-11-11T19:28:46+00:00"
updated_at: "2026-11-11T19:30:27+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126771", "first_seen_at": "2026-11-11T19:28:46+00:00"}]
exploit_sources: []
---

# OpsTree REMS: uploaded attachments run scripts in other users' browsers

Link for people: https://infrastack.ai/live/CVE-2026-126771 (this .md is for agents)

OpsTree REMS through 1.0.0 accepts attachments with a spoofed text/html Content-Type, so a file named like test.html.pdf renders as HTML when previewed. An authenticated attacker can run JavaScript in the browsers of other users who open the preview.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-11-11T19:28:46+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126771

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/opstree-rems-through-1.0.0-stored-xss-via-attachment-upload-and-preview

## From the sources

OpsTree REMS through 1.0.0 contains a stored cross-site scripting vulnerability that allows authenticated attackers to inject scripts by uploading attachments with spoofed text/html Content-Type. Attackers can upload HTML files named like test.html.pdf that render in the REMS origin via Preview, executing JavaScript in victims' browsers.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_