How severe is CVE-2021-37703?

CVE-2021-37703 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-37703 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37703?

CVE-2021-37703 primarily affects Discourse. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-37703?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-37703 published?

CVE-2021-37703 was published on 2021-08-13 and last updated on 2026-06-17.

CVE-2021-37703

CVE-2021-37703 is a medium-severity vulnerability in Discourse with a CVSS 3.x base score of 4.3. 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-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Discourse
Published: 2021-08-13
Last modified: 2026-06-17

Description

Discourse is an open-source platform for community discussion. In Discourse before versions 2.7.8 and 2.8.0.beta5, a user's read state for a topic such as the last read post number and the notification level is exposed.

Frequently asked questions

What is CVE-2021-37703?: Discourse is an open-source platform for community discussion. In Discourse before versions 2.7.8 and 2.8.0.beta5, a user's read state for a topic such as the last read post number and the notification level is exposed.
How severe is CVE-2021-37703?: CVE-2021-37703 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-37703 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37703?: CVE-2021-37703 primarily affects Discourse. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-37703?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-37703 published?: CVE-2021-37703 was published on 2021-08-13 and last updated on 2026-06-17.

References

Affected products (5)

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:*:*:*:*:*:*

More vulnerabilities in Discourse

CVE-2021-41163 — Critical (CVSS 10.0): Discourse is an open source platform for community discussion. In affected versions maliciously crafted requests could…
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…
CVE-2025-48877 — Critical (CVSS 9.8): Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of…
CVE-2022-36066 — Critical (CVSS 9.1): Discourse is an open source discussion platform. In versions prior to 2.8.9 on the `stable` branch and prior to…
CVE-2022-39356 — High (CVSS 8.9): Discourse is a platform for community discussion. Users who receive an invitation link that is not scoped to a single…
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