How severe is CVE-2021-41163?

CVE-2021-41163 has a CVSS 3.x base score of 10.0, 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-2021-41163 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41163?

CVE-2021-41163 primarily affects Discourse. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-41163?

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-2021-41163 published?

CVE-2021-41163 was published on 2021-10-20 and last updated on 2026-06-17.

CVE-2021-41163

CVE-2021-41163 is a critical-severity vulnerability in Discourse with a CVSS 3.x base score of 10.0. Its EPSS exploit-prediction score of 20% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-74.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 7.5
EPSS exploit prediction: 20% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Discourse
Published: 2021-10-20
Last modified: 2026-06-17

Description

Discourse is an open source platform for community discussion. In affected versions maliciously crafted requests could lead to remote code execution. This resulted from a lack of validation in subscribe_url values. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. To workaround the issue without updating, requests with a path starting /webhooks/aws path could be blocked at an upstream proxy.

Frequently asked questions

What is CVE-2021-41163?: Discourse is an open source platform for community discussion. In affected versions maliciously crafted requests could lead to remote code execution. This resulted from a lack of validation in subscribe_url values. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. To workaround the issue without updating, requests with a path starting /webhooks/aws path could be blocked at an upstream proxy.
How severe is CVE-2021-41163?: CVE-2021-41163 has a CVSS 3.x base score of 10.0, 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-2021-41163 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41163?: CVE-2021-41163 primarily affects Discourse. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-41163?: 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-2021-41163 published?: CVE-2021-41163 was published on 2021-10-20 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2.8.0:beta1:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2.8.0:beta2:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2.8.0:beta3:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2.8.0:beta4:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2.8.0:beta5:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2.8.0:beta6:*:*:*:*:*:*

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CVE-2025-53102 — Critical (CVSS 9.8): Discourse is an open-source community discussion platform. Prior to version 3.4.7 on the `stable` branch and version…
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