What is CVE-2021-3131?

CVE-2021-3131 is a high-severity vulnerability in 1c 1c\, classified under Inadequate Encryption Strength. CVSS score: 7.5/10. Published 2021-01-13.

How severe is CVE-2021-3131?

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

Is CVE-2021-3131 known to be exploited?

14 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in 1c 1c\

CVE-2021-3131

The Web server in 1C:Enterprise 8 before 8.3.17.1851 sends base64 encoded credentials in the creds URL parameter.

Published 2021-01-13 · 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: 0.010 (59.9th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 59.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

1c 1c\ — versions enterprise
1c 1c\:enterprise

Weakness classification (CWE)

CWE-326 — Inadequate Encryption Strength

Public proof-of-concept exploits

References

github.com/jet-pentest/CVE-2021-3131 (Third Party Advisory)

Frequently asked questions

What is CVE-2021-3131?: CVE-2021-3131 is a high-severity vulnerability in 1c 1c\, classified under Inadequate Encryption Strength. CVSS score: 7.5/10. Published 2021-01-13.
How severe is CVE-2021-3131?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-3131 known to be exploited?: 14 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.