What is CVE-2016-3953?

CVE-2016-3953 is a critical-severity vulnerability in Web2py, classified under Use of Hard-coded Credentials. CVSS score: 9.8/10. Published 2018-02-06.

How severe is CVE-2016-3953?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Web2py

CVE-2016-3953

The sample web application in web2py before 2.14.2 might allow remote attackers to execute arbitrary code via vectors involving use of a hardcoded encryption key when calling the session.connect function.

Published 2018-02-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.033 (88.2th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 88.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.033 · newest: 0.033 · change: 0.000

Affected products

Web2py

Weakness classification (CWE)

CWE-798 — Use of Hard-coded Credentials

References

devco.re/blog/2017/01/03/web2py-unserialize-code-execution-CVE-2016-3957/ (Technical Description, Exploit, Third Party Advisory)
github.com/web2py/web2py/blob/R-2.14.1/applications/examples/models/session.py (Third Party Advisory)
usn.ubuntu.com/4030-1/ (vendor-advisory)

Frequently asked questions

What is CVE-2016-3953?: CVE-2016-3953 is a critical-severity vulnerability in Web2py, classified under Use of Hard-coded Credentials. CVSS score: 9.8/10. Published 2018-02-06.
How severe is CVE-2016-3953?: Critical severity. CVSS v3 base score is 9.8 out of 10.