What’s Vulnerable › Vulnerabilities

CVE-2016-3957

• Severity: critical (CVSS 9.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2018-02-06 · updated 2026-06-17
• Weakness: CWE-502

Description

The secure_load function in gluon/utils.py in web2py before 2.14.2 uses pickle.loads to deserialize session information stored in cookies, which might allow remote attackers to execute arbitrary code by leveraging knowledge of encryption_key.

Affected products

• web2py: before 2.14.2 — fixed in 2.14.2

How to fix

Upgrade to a fixed version: web2py 2.14.2. Check the vendor advisory for mitigations.

References

• https://devco.re/blog/2017/01/03/web2py-unserialize-code-execution-CVE-2016-3957/
• https://github.com/web2py/web2py/blob/R-2.14.1/gluon/utils.py#L200
• https://usn.ubuntu.com/4030-1/
• https://devco.re/blog/2017/01/03/web2py-unserialize-code-execution-CVE-2016-3957/
• https://github.com/web2py/web2py/blob/R-2.14.1/gluon/utils.py#L200
• https://usn.ubuntu.com/4030-1/

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