How severe is CVE-2021-44657?

CVE-2021-44657 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-44657 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-44657?

CVE-2021-44657 affects Stackstorm. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-44657?

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.

When was CVE-2021-44657 published?

CVE-2021-44657 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-44657

CVE-2021-44657 is a high-severity vulnerability in Stackstorm with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 9.0
EPSS exploit prediction: 2% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Stackstorm
Published: 2021-12-15
Last modified: 2026-06-17

Description

In StackStorm versions prior to 3.6.0, the jinja interpreter was not run in sandbox mode and thus allows execution of unsafe system commands. Jinja does not enable sandboxed mode by default due to backwards compatibility. Stackstorm now sets sandboxed mode for jinja by default.

Frequently asked questions

What is CVE-2021-44657?: In StackStorm versions prior to 3.6.0, the jinja interpreter was not run in sandbox mode and thus allows execution of unsafe system commands. Jinja does not enable sandboxed mode by default due to backwards compatibility. Stackstorm now sets sandboxed mode for jinja by default.
How severe is CVE-2021-44657?: CVE-2021-44657 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-44657 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-44657?: CVE-2021-44657 affects Stackstorm. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-44657?: 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.
When was CVE-2021-44657 published?: CVE-2021-44657 was published on 2021-12-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:stackstorm:stackstorm:*:*:*:*:*:*:*:*

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