PatchTheCVECVE-2021-3766: objection.js is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Po
CVE-2021-3766 is a critical-severity flaw (CVSS 9.8) affecting objection. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
objection.js is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Why this priority
- Critical severity
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.5% (top 26%) |
| CISA exploited list | No |
| Weakness | CWE-1321 |
| Published | 2021-09-06 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-3766?
objection: upgrade to 2.2.16. Exact commands for each OS are on this page.
Is CVE-2021-3766 being exploited?
CVE-2021-3766 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-3766 affect?
CVE-2021-3766 affects objection. Severity is critical (CVSS 9.8). objection.js is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
How urgent is CVE-2021-3766?
Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action