CVE-2026-33863
Convict has prototype pollution via load(), loadFile(), and schema initialization
Impact
Two unguarded prototype pollution paths exist, not covered by previous fixes:
config.load()/config.loadFile()—overlay()recursively merges config data without checking for forbidden keys. Input containing__proto__orconstructor.prototype(e.g. from a JSON file) causes the recursion to reachObject.prototypeand write attacker-controlled values onto it.- Schema initialization — passing a schema with
constructor.prototype.*keys toconvict({...})causes default-value propagation to write directly toObject.prototypeat startup.
Depending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE.
Workarounds
Do not pass untrusted data to load(), loadFile(), or convict().
Resources
Prior advisory: GHSA-44fc-8fm5-q62h Related issue: https://github.com/mozilla/node-convict/issues/423
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
What each source reports
GitHub Advisories Score usedGHSA-hf2r-9gf9-rwch
Convict has prototype pollution via load(), loadFile(), and schema initialization
Impact
Two unguarded prototype pollution paths exist, not covered by previous fixes:
config.load()/config.loadFile()—overlay()recursively merges config data without checking for forbidden keys. Input containing__proto__orconstructor.prototype(e.g. from a JSON file) causes the recursion to reachObject.prototypeand write attacker-controlled values onto it.- Schema initialization — passing a schema with
constructor.prototype.*keys toconvict({...})causes default-value propagation to write directly toObject.prototypeat startup.
Depending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE.
Workarounds
Do not pass untrusted data to load(), loadFile(), or convict().
Resources
Prior advisory: GHSA-44fc-8fm5-q62h Related issue: https://github.com/mozilla/node-convict/issues/423
- Record
GHSA-hf2r-9gf9-rwch- CVSS 4.0
- 9.4 Critical
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSVGHSA-hf2r-9gf9-rwch
Convict has prototype pollution via load(), loadFile(), and schema initialization
Impact
Two unguarded prototype pollution paths exist, not covered by previous fixes:
config.load()/config.loadFile()—overlay()recursively merges config data without checking for forbidden keys. Input containing__proto__orconstructor.prototype(e.g. from a JSON file) causes the recursion to reachObject.prototypeand write attacker-controlled values onto it.- Schema initialization — passing a schema with
constructor.prototype.*keys toconvict({...})causes default-value propagation to write directly toObject.prototypeat startup.
Depending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE.
Workarounds
Do not pass untrusted data to load(), loadFile(), or convict().
Resources
Prior advisory: GHSA-44fc-8fm5-q62h Related issue: https://github.com/mozilla/node-convict/issues/423
- Record
GHSA-hf2r-9gf9-rwch- CVSS 4.0
- 9.4 Critical
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - Weakness
- CWE-1321
- Updated
- 2026-11-02
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-33863 is a critical vulnerability (CVSS 9.4) in convict, published March 26, 2026. No source lists public exploit code. Fixed in convict 6.2.5.