What is CVE-2021-27935?

CVE-2021-27935 is a high-severity vulnerability in Adguard Home, classified under Insufficiently Protected Credentials. CVSS score: 7.5/10. Published 2021-03-03.

How severe is CVE-2021-27935?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Adguard Home

CVE-2021-27935

An issue was discovered in AdGuard before 0.105.2. An attacker able to get the user's cookie is able to bruteforce their password offline, because the hash of the password is stored in the cookie.

Published 2021-03-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.050 (91.9th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 91.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.050 · newest: 0.050 · change: 0.000

Affected products

Adguard Home

Weakness classification (CWE)

CWE-522 — Insufficiently Protected Credentials

References

github.com/AdguardTeam/AdGuardHome/issues/2470 (Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-27935?: CVE-2021-27935 is a high-severity vulnerability in Adguard Home, classified under Insufficiently Protected Credentials. CVSS score: 7.5/10. Published 2021-03-03.
How severe is CVE-2021-27935?: High severity. CVSS v3 base score is 7.5 out of 10.