CVE-2026-7888
CVE-2026-7888 is a high-severity vulnerability with a CVSS 4.0 base score of 8.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.
Key facts
- Severity: High (CVSS 4.0 base score 8.4)
- EPSS exploit prediction: 0% (7th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-34164
- Weakness: CWE-502
- Published:
- Last modified:
Description
Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowed_classes restriction. An unauthenticated attacker may trigger arbitrary PHP object instantiation if a malicious serialized payload has been placed in the database. Thanks XananasX7 and Sanjorn Keeratirungsan (dizconnect) for both independently reporting. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.4 with vector CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N.
Frequently asked questions
- What is CVE-2026-7888?
- Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowed_classes restriction. An unauthenticated attacker may trigger arbitrary PHP object instantiation if a malicious serialized payload has been placed in the database. Thanks XananasX7 and Sanjorn Keeratirungsan (dizconnect) for both independently reporting. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.4 with vector CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N.
- How severe is CVE-2026-7888?
- CVE-2026-7888 has a CVSS 4.0 base score of 8.4, rated high severity.
- Is CVE-2026-7888 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-7888?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-7888 have an EU (EUVD) identifier?
- Yes. CVE-2026-7888 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34164.
- When was CVE-2026-7888 published?
- CVE-2026-7888 was published on 2026-06-03 and last updated on 2026-06-17.
References
Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities
- CVE-2026-41104 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Planetary Computer Pro allows an unauthorized attacker to disclose…
- CVE-2026-43633 — Critical (CVSS 10.0): HestiaCP versions 1.9.0 through 1.9.4 contain a deserialization vulnerability in the web terminal component caused by a…
- CVE-2026-33819 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Bing allows an unauthorized attacker to execute code over a network.
- CVE-2026-20131 — Critical (CVSS 10.0): A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could…
- CVE-2026-25632 — Critical (CVSS 10.0): EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water…
- CVE-2025-14931 — Critical (CVSS 10.0): Hugging Face smolagents Remote Python Executor Deserialization of Untrusted Data Remote Code Execution Vulnerability.…
Browse all CWE-502 (Deserialization of Untrusted Data) vulnerabilities →