CVE-2026-27579

High

Published: 21 February 2026

Published

21 February 2026

Modified

15 April 2026

KEV Added

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Patch

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CVSS Score 7.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N

EPSS Score 0.0001 0.7th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-27579 is a high-severity Origin Validation Error (CWE-346) vulnerability. Its CVSS base score is 7.4 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 0.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique.

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

IA-9 Service Identification and Authentication

addresses: CWE-346

Requires unique identification of the service before communications, addressing failures to validate the origin of the interaction.

SC-11 Trusted Path

addresses: CWE-346

Trusted path establishment enforces validation that the communication originates from and reaches only the intended trusted system components.

SC-20 Secure Name/Address Resolution Service (Authoritative Source)

addresses: CWE-346

Enforces validation of the true origin of DNS responses via signatures and chain-of-trust mechanisms.

SC-21 Secure Name/Address Resolution Service (Recursive or Caching Resolver)

addresses: CWE-346

Enforces origin validation of name/address data, eliminating reliance on unverified or impersonated DNS sources.

SC-23 Session Authenticity

addresses: CWE-346

Mandates origin validation so that only legitimate endpoints can continue the authenticated session.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1566.002 Spearphishing Link Initial Access

Adversaries may send spearphishing emails with a malicious link in an attempt to gain access to victim systems.

attack.mitre.org →

Why these techniques?

CORS misconfiguration in public-facing CollabPlatform/Appwrite instance directly enables cross-origin authenticated requests; exploitation explicitly requires spearphishing link to lure authenticated user to attacker-controlled origin for data exfil.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

CollabPlatform is a full-stack, real-time doc collaboration platform. In all versions of CollabPlatform, the Appwrite project used by the application is misconfigured to allow arbitrary origins in CORS responses while also permitting credentialed requests. An attacker-controlled domain can issue authenticated…

cross-origin requests and read sensitive user account information, including email address, account identifiers, and MFA status. The issue did not have a fix at the time of publication.

Deeper analysisAI

CVE-2026-27579 is a cross-origin resource sharing (CORS) misconfiguration vulnerability affecting all versions of CollabPlatform, a full-stack real-time document collaboration platform. The issue resides in the Appwrite project used by the application, which is incorrectly set to allow arbitrary origins in CORS responses while also permitting credentialed requests. This enables unauthorized cross-origin access to sensitive data.

Attackers can exploit this vulnerability from any network location without privileges by controlling a malicious domain and tricking an authenticated user into interacting with it, such as via a phishing link (user interaction required). Successful exploitation allows the attacker to issue authenticated cross-origin requests and exfiltrate sensitive user account information from the Appwrite instance, including email addresses, account identifiers, and MFA status. The vulnerability has a CVSS v3.1 base score of 7.4 (AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N), reflecting high confidentiality impact with changed scope.

The GitHub security advisory at https://github.com/karnop/realtime-collaboration-platform/security/advisories/GHSA-qh5m-p8jh-hx88, published on 2026-02-21, states that no fix was available at the time of disclosure. Practitioners should monitor for updates from the CollabPlatform maintainers and consider isolating or reconfiguring Appwrite instances to enforce strict origin policies in the interim.