Stored Cross-Site Scripting Vulnerability in OpsTree REMS Product
CVE-2026-126771

5.1MEDIUM

Key Information:

Vendor

Opstree Solutions

Status
Rems
Vendor
CVE Published:
11 November 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-126771?

The OpsTree REMS application up to version 1.0.0 is vulnerable to a stored cross-site scripting flaw that enables authenticated attackers to inject malicious scripts. This vulnerability arises when attackers upload attachments with a deceptive Content-Type of text/html, such as files masquerading as test.html.pdf. Once uploaded, these files can be previewed within the REMS application, allowing the injected JavaScript to execute in the browsers of users who access the application, potentially leading to harmful actions and data exposure.

Affected Version(s)

REMS 0 <= 1.0.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-126771 - Proof of Concept

References

https://gist.github.com/neelkotnis/ddf75e2cb7192180e6c961...
technical-descriptionexploit
https://opstree.com/rems-ai-powered-observability/
product
https://www.vulncheck.com/advisories/opstree-rems-through...
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Neel Saurabh Kotnis
.