How severe is CVE-2021-34817?

CVE-2021-34817 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-34817 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34817?

CVE-2021-34817 affects Etherpad. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34817?

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

When was CVE-2021-34817 published?

CVE-2021-34817 was published on 2021-07-19 and last updated on 2026-06-17.

CVE-2021-34817

CVE-2021-34817 is a medium-severity vulnerability in Etherpad with a CVSS 3.x base score of 6.1. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Etherpad
Published: 2021-07-19
Last modified: 2026-06-17

Description

A Cross-Site Scripting (XSS) issue in the chat component of Etherpad 1.8.13 allows remote attackers to inject arbitrary JavaScript or HTML by importing a crafted pad.

Frequently asked questions

What is CVE-2021-34817?: A Cross-Site Scripting (XSS) issue in the chat component of Etherpad 1.8.13 allows remote attackers to inject arbitrary JavaScript or HTML by importing a crafted pad.
How severe is CVE-2021-34817?: CVE-2021-34817 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-34817 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34817?: CVE-2021-34817 affects Etherpad. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34817?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-34817 published?: CVE-2021-34817 was published on 2021-07-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:etherpad:etherpad:1.8.13:*:*:*:*:*:*:*

More vulnerabilities in Etherpad

CVE-2021-43802 — Critical (CVSS 9.9): Etherpad is a real-time collaborative editor. In versions prior to 1.8.16, an attacker can craft an `*.etherpad` file…
CVE-2018-9326 — Critical (CVSS 9.8): Etherpad 1.6.3 before 1.6.4 allows an attacker to execute arbitrary code.
CVE-2018-6835 — Critical (CVSS 9.8): node/hooks/express/apicalls.js in Etherpad Lite before v1.6.3 mishandles JSONP, which allows remote attackers to bypass…
CVE-2018-9327 — High (CVSS 8.1): Etherpad 1.5.x and 1.6.x before 1.6.4 allows an attacker to execute arbitrary code on the server. The instance has to…
CVE-2020-22785 — High (CVSS 7.5): Etherpad < 1.8.3 is affected by a missing lock check which could cause a denial of service. Aggressively targeting…
CVE-2020-22782 — High (CVSS 7.5): Etherpad < 1.8.3 is affected by a denial of service in the import functionality. Upload of binary file to the import…

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