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CVE-2021-32816

Regular expression Denial of Service in ProtonMail

HIGH
7.5
CVSS Score
Published: May 14, 2021 at 05:35 PM UTC
Updated: June 17, 2026 at 03:53 AM UTC
1 product affected across 1 vendorProtonmail

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Severity
HIGH7.5
Exploit prediction
EPSS 1%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Protonmail· Protonmail
95%
v < 3.16.60
Affected range stops below 3.16.60, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

x_refsource_MISCPatchThird Party Advisory
Source: [email protected]
https://github.com/ProtonMail/WebClient/commit/6687fbb867ef872c96cf4fde68cb6e9c58d3fddc
x_refsource_CONFIRMExploitThird Party Advisory
Source: [email protected]
https://securitylab.github.com/advisories/GHSL-2021-027-redos-ProtonMail/

CVSS

7.5HIGH[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400

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