How severe is CVE-2021-22958?

CVE-2021-22958 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-22958 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-22958?

CVE-2021-22958 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-22958?

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-2021-22958 published?

CVE-2021-22958 was published on 2021-10-07 and last updated on 2026-06-17.

CVE-2021-22958

CVE-2021-22958 is a critical-severity vulnerability in Concretecms Concrete Cms with a CVSS 3.x base score of 9.8. 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-918.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-918
Affected product: Concretecms Concrete Cms
Published: 2021-10-07
Last modified: 2026-06-17

Description

A Server-Side Request Forgery vulnerability was found in concrete5 < 8.5.5 that allowed a decimal notation encoded IP address to bypass the limitations in place for localhost allowing interaction with local services. Impact can vary depending on services exposed.CVSSv2.0 AV:A/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N

Frequently asked questions

What is CVE-2021-22958?: A Server-Side Request Forgery vulnerability was found in concrete5 < 8.5.5 that allowed a decimal notation encoded IP address to bypass the limitations in place for localhost allowing interaction with local services. Impact can vary depending on services exposed.CVSSv2.0 AV:A/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N
How severe is CVE-2021-22958?: CVE-2021-22958 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-22958 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22958?: CVE-2021-22958 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-22958?: 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-2021-22958 published?: CVE-2021-22958 was published on 2021-10-07 and last updated on 2026-06-17.

References

Affected products (1)

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

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