Deserialization in Cypht-Org Cypht
CVE-2026-71981
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.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.010 (61.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.010 · change: +0.004
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/cypht-org/cypht/releases/tag/v2.12.2 (release-notes)
- github.com/cypht-org/cypht/pull/2073 (issue-tracking)
- github.com/cypht-org/cypht/commit/e4aa2f34e33f9328e8c93514cc3966fc3d99925e (patch)
- www.vulncheck.com/advisories/cypht-php-object-injection-rce-via-back-query-para… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-71981?
- CVE-2026-71981 is a high-severity vulnerability in Cypht-Org Cypht, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2026-09-01.
- How severe is CVE-2026-71981?
- High severity. CVSS v3 base score is 8.8 out of 10.
- Is CVE-2026-71981 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.