Skip to content
Fencer Vulns
critical 9.8

CVE-2021-25948 json

Prototype Pollution

published 2021-06-10 5 y ago modified 2026-06-17 4 mo ago also GHSA-x3wr-v4wx-5qpc , EUVD-2021-1422

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

Prototype pollution vulnerability in 'expand-hash' versions 0.1.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

Exploit prediction

3.30% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • whitesourcesoftware.com https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25948 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/doowb/expand-hash/blob/556913f6c2f05848110b5b8261cfc78e5ce3dc77/index.js#L19 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm expand-hash
<=1.0.1
 no fix listed

Affected products

  • n/a expand-hash

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes
  • CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.