How severe is CVE-2021-25294?

CVE-2021-25294 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-2021-25294 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-25294?

CVE-2021-25294 affects Opencats. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-25294?

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-2021-25294 published?

CVE-2021-25294 was published on 2021-01-18 and last updated on 2026-06-17.

CVE-2021-25294

CVE-2021-25294 is a critical-severity vulnerability in Opencats with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 11% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 11% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Opencats
Published: 2021-01-18
Last modified: 2026-06-17

Description

OpenCATS through 0.9.5-3 unsafely deserializes index.php?m=activity requests, leading to remote code execution. This occurs because lib/DataGrid.php calls unserialize for the parametersactivity:ActivityDataGrid parameter. The PHP object injection exploit chain can leverage an __destruct magic method in guzzlehttp.

Frequently asked questions

What is CVE-2021-25294?: OpenCATS through 0.9.5-3 unsafely deserializes index.php?m=activity requests, leading to remote code execution. This occurs because lib/DataGrid.php calls unserialize for the parametersactivity:ActivityDataGrid parameter. The PHP object injection exploit chain can leverage an __destruct magic method in guzzlehttp.
How severe is CVE-2021-25294?: CVE-2021-25294 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-2021-25294 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-25294?: CVE-2021-25294 affects Opencats. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-25294?: 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-2021-25294 published?: CVE-2021-25294 was published on 2021-01-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:opencats:opencats:*:*:*:*:*:*:*:*

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