Cyber Resilience

CVE-2026-27369

HighRCE

Published: 05 March 2026

Published
05 March 2026
Modified
22 April 2026
KEV Added
—
Patch
—
CVSS Score v3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0031 22.3th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-27369 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 22.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Deeper analysis

CVE-2026-27369 is a Deserialization of Untrusted Data vulnerability (CWE-502) in the BoldThemes Celeste WordPress theme, enabling Object Injection. The issue affects Celeste versions from n/a through 1.3.6, as disclosed on 2026-03-05.

The vulnerability carries a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H). Remote unauthenticated attackers can exploit it over the network with high attack complexity and no user interaction, potentially achieving high impacts on confidentiality, integrity, and availability through object injection.

Mitigation details are available in the Patchstack advisory at https://patchstack.com/database/Wordpress/Theme/celeste/vulnerability/wordpress-celeste-theme-1-3-6-php-object-injection-vulnerability?_s_id=cve.

OWASP Top 10 for Web (2025)

A08:2025 Software or Data Integrity Failures

EU & UK References

Vulnerability details

Deserialization of Untrusted Data vulnerability in BoldThemes Celeste celeste allows Object Injection.This issue affects Celeste: from n/a through <= 1.3.6.

CWE(s)
CWE-502

Related Threats

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 →
T1505.003 Web Shell Persistence
Adversaries may backdoor web servers with web shells to establish persistent access to systems.
attack.mitre.org →
Why these techniques?

Unauthenticated remote PHP object injection (deserialization) in a public-facing WordPress theme directly maps to exploitation of public-facing applications (T1190). Successful exploitation with available gadget chains commonly results in arbitrary code execution or web shell deployment on the server (T1505.003).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2017-20207Shared CWE-502
CVE-2025-31103Shared CWE-502
CVE-2026-3296Shared CWE-502
CVE-2026-25031Shared CWE-502
CVE-2025-55010Shared CWE-502
CVE-2026-25029Shared CWE-502
CVE-2017-20208Shared CWE-502
CVE-2026-35537Shared CWE-502
CVE-2026-2471Shared CWE-502
CVE-2025-62368Shared CWE-502

Affected Assets

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly mitigates CVE-2026-27369 by requiring timely patching of the vulnerable BoldThemes Celeste WordPress theme to versions beyond 1.3.6, eliminating the deserialization flaw.

SI-10 Information Input Validation good match
prevent

Prevents object injection by enforcing validation and sanitization of untrusted data before deserialization in the Celeste theme.

RA-5 Vulnerability Monitoring and Scanning partial match
detect

Identifies the presence of the vulnerable Celeste theme through vulnerability scanning, enabling proactive remediation of CVE-2026-27369.

References