How severe is CVE-2021-40102?

CVE-2021-40102 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2021-40102 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40102?

CVE-2021-40102 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40102?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-40102 published?

CVE-2021-40102 was published on 2021-09-24 and last updated on 2026-06-17.

CVE-2021-40102

CVE-2021-40102 is a critical-severity vulnerability in Concretecms Concrete Cms with a CVSS 3.x base score of 9.1. 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: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Concretecms Concrete Cms
Published: 2021-09-24
Last modified: 2026-06-17

Description

An issue was discovered in Concrete CMS through 8.5.5. Arbitrary File deletion can occur via PHAR deserialization in is_dir (PHP Object Injection associated with the __wakeup magic method).

Frequently asked questions

What is CVE-2021-40102?: An issue was discovered in Concrete CMS through 8.5.5. Arbitrary File deletion can occur via PHAR deserialization in is_dir (PHP Object Injection associated with the __wakeup magic method).
How severe is CVE-2021-40102?: CVE-2021-40102 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-40102 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40102?: CVE-2021-40102 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40102?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-40102 published?: CVE-2021-40102 was published on 2021-09-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*

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