What’s Vulnerable › Vulnerabilities

CVE-2026-71981: Cypht < 2.12.2 PHP Object Injection RCE via back_query Parameter

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-01 · updated 2026-09-08
• Weakness: CWE-502

Description

Cypht before 2.12.2 contains a PHP object injection vulnerability that allows authenticated attackers to execute arbitrary operating system commands by supplying a crafted PHP object graph in the back_query GET parameter of the logout handler. Attackers can pass a base64-encoded serialized payload through this parameter, which is decoded and passed directly to unserialize() without an allow-list, signature check, or type restriction, enabling gadget-chain exploitation to achieve remote code execution as the web server process.

Affected products

• cypht-org cypht: before 2.12.2 — fixed in 2.12.2

How to fix

Upgrade to a fixed version: cypht-org cypht 2.12.2. Check the vendor advisory for mitigations.

References

• https://github.com/cypht-org/cypht/commit/e4aa2f34e33f9328e8c93514cc3966fc3d99925e
• https://github.com/cypht-org/cypht/pull/2073
• https://github.com/cypht-org/cypht/releases/tag/v2.12.2
• https://www.vulncheck.com/advisories/cypht-php-object-injection-rce-via-back-query-parameter

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