PatchTheCVECVE-2021-23663: All versions of package sey are vulnerable to Prototype Pollution via the deepmerge() function.
CVE-2021-23663 is a medium-severity flaw (CVSS 6.5) affecting sey. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
All versions of package sey are vulnerable to Prototype Pollution via the deepmerge() function.
Why this priority
- Public exploit reference
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.2% (top 32%) |
| CISA exploited list | No |
| Weakness | CWE-1321 |
| Published | 2021-12-10 |
| 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-2021-23663?
sey: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2021-23663 being exploited?
CVE-2021-23663 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-2021-23663 affect?
CVE-2021-23663 affects sey. Severity is medium (CVSS 6.5). All versions of package sey are vulnerable to Prototype Pollution via the deepmerge() function.
How urgent is CVE-2021-23663?
Priority 50/100. Public exploit reference; Remotely exploitable, no login, no user action