CVE-2021-32816: ProtonMail Web Client is the official AngularJS web client for the ProtonMail secure email service

Q: How do I fix CVE-2021-32816?

protonmail: upgrade to 3.16.60. Exact commands for each OS are on this page.

Q: Is CVE-2021-32816 being exploited?

CVE-2021-32816 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-32816 affect?

CVE-2021-32816 affects protonmail. Severity is medium (CVSS 6.5). 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. Ther

Q: How urgent is CVE-2021-32816?

Priority 44/100. Public exploit reference

This month

MEDIUM 6.5UPGRADE

CVE-2021-32816 is a medium-severity flaw (CVSS 6.5) affecting protonmail. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-400
Published	2021-05-14
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: protonmail

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-05-14 18:15 UTCPublished CVE record published
2026-06-17 03:53 UTCUpdated Record last modified

protonmail protonmail UPGRADE

Affected: < 3.16.60

Fixed in: 3.16.60

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy protonmail || rpm -q protonmail || protonmail --version

2. UPGRADE to 3.16.60 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade protonmail

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade protonmail

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-32816?

protonmail: upgrade to 3.16.60. Exact commands for each OS are on this page.

Is CVE-2021-32816 being exploited?

CVE-2021-32816 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-32816 affect?

CVE-2021-32816 affects protonmail. Severity is medium (CVSS 6.5). 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. Ther

How urgent is CVE-2021-32816?

Priority 44/100. Public exploit reference

References

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