Cyber Resilience

CVE-2026-27579

Published
21 February 2026
Modified
15 April 2026
CVSS Score v3.1 7.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
EPSS Score 0.0023 13th percentile
Risk Priority 52 floored blend · peak EPSS

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 DHCP Spoofing (T1557.003); ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and IA-3 (Device Identification and Authentication) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

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.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1557.003 DHCP Spoofing Credential Access
Adversaries may redirect network traffic to adversary-owned systems by spoofing Dynamic Host Configuration Protocol (DHCP) traffic and acting as a malicious DHCP server on the victim network.
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
T1557.001 Name Resolution Poisoning and SMB Relay Credential Access
By responding to LLMNR/NBT-NS/mDNS network traffic, adversaries may spoof an authoritative source for name resolution to force communication with an adversary controlled system.
T1557.002 ARP Cache Poisoning Credential Access
Adversaries may poison Address Resolution Protocol (ARP) caches to position themselves between the communication of two or more networked devices.
T1557.004 Evil Twin Credential Access
Adversaries may host seemingly genuine Wi-Fi access points to deceive users into connecting to malicious networks as a way of supporting follow-on behaviors such as [Network Sniffing](https://attack.
T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-7581Shared CWE-346, CWE-942
CVE-2024-25124Shared CWE-346, CWE-942
CVE-2025-4839Shared CWE-346, CWE-942
CVE-2026-7643Shared CWE-346, CWE-942
CVE-2026-6143Shared CWE-346, CWE-942
CVE-2026-45021Shared CWE-346, CWE-942
CVE-2025-11304Shared CWE-346, CWE-942
CVE-2025-1083Shared CWE-346, CWE-942
CVE-2025-4542Shared CWE-346, CWE-942
CVE-2026-44184Shared CWE-346, CWE-942

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V3.4.3
  • V3.4.6
  • V3.5.2

Mitigating Controls (NIST 800-53 r5) AI

Information flow enforcement directly requires validating the source of data before allowing transmission or receipt.

Device identification and authentication mandates verifying the source before establishing connections.

Session authenticity mechanisms require validation that communications originate from the expected party.

Boundary protection at interfaces enforces checks on the origin of incoming communications.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 mostly match
prevents

Authentication directly verifies the source of users/services/hardware, mitigating origin validation failures.

PR.AA-04 mostly match
prevents

Verifying identity assertions enforces origin validation for conveyed claims.

PR.PS-01 mostly match
prevents

Hardened configuration baselines and reviews directly prevent permissive CSP or cross-domain policies.

PR.PS-06 mostly match
prevents

Secure SDLC activities include review and testing of web security policies to avoid untrusted domains.

ID.AM-03 partial match
prevents

Documenting authorized flows supports origin validation by defining expected sources.

ID.RA-01 partial match
prevents

Vulnerability identification processes can surface permissive policy misconfigurations.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect overly permissive cross-domain policies but does not prevent their initial introduction.

mitigates

Network security controls enforce origin validation at network boundaries.

mitigates

Security of network services includes validating the authenticity of service endpoints.

mitigates

Network segregation reduces exposure but does not directly validate origins.

degrades

Web filtering can block untrusted domains at the network level, partially mitigating permissive cross-domain policies.

prevents

Application security requirements explicitly call for origin validation of inputs and communications.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-346
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-346
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-346

References