How severe is CVE-2021-32816?

CVE-2021-32816 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-32816 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-32816?

CVE-2021-32816 affects Protonmail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-32816?

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

When was CVE-2021-32816 published?

CVE-2021-32816 was published on 2021-05-14 and last updated on 2026-06-17.

CVE-2021-32816

CVE-2021-32816 is a medium-severity vulnerability in Protonmail with a CVSS 3.x base score of 6.5. 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-400.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Protonmail
Published: 2021-05-14
Last modified: 2026-06-17

Description

ProtonMail Web Client is the official AngularJS web client for the ProtonMail secure email service. ProtonMail Web Client before version 3.16.60 has a regular expression denial-of-service vulnerability. This was fixed in commit 6687fb. There is a full report available in the referenced GHSL-2021-027.

Frequently asked questions

What is CVE-2021-32816?: ProtonMail Web Client is the official AngularJS web client for the ProtonMail secure email service. ProtonMail Web Client before version 3.16.60 has a regular expression denial-of-service vulnerability. This was fixed in commit 6687fb. There is a full report available in the referenced GHSL-2021-027.
How severe is CVE-2021-32816?: CVE-2021-32816 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-32816 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-32816?: CVE-2021-32816 affects Protonmail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-32816?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-32816 published?: CVE-2021-32816 was published on 2021-05-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:protonmail:protonmail:*:*:*:*:*:*:*:*

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