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Fencer Vulns
critical 9.1

CVE-2021-42581 json

Prototype poisoning in function mapObjIndexed in Ramda 0.27.0 and earlier allows attackers to compromise integrity or availability of appli…

published 2022-05-10 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29546

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

Prototype poisoning in function mapObjIndexed in Ramda 0.27.0 and earlier allows attackers to compromise integrity or availability of application via supplying a crafted object (that contains an own property "__proto__") as an argument to the function. NOTE: the vendor disputes this because the observed behavior only means that a user can create objects that the user didn't know would contain custom prototypes

Patch / fix

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-42581 updated cvss 9.1

ramda: prototype poisoning

  • Red Hat OpenShift Service Mesh 2.1 servicemesh-grafana, openshift-service-mesh/kiali-rhel8 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/application-ui-rhel8
    affected: no fix planned “Will not fix”
  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8
    affected: no fix available
  • Red Hat Decision Manager 7 ramda Red Hat Process Automation 7 ramda
    affected: no fix available “Fix deferred”
  • Red Hat Ceph Storage 6.1 Tools rhceph/rhceph-6-dashboard-rhel9 6-75
    fixed: vendor fix RHSA-2023:3642
  • Red Hat Migration Toolkit for Virtualization migration-toolkit-virtualization/mtv-ui-rhel8 Red Hat A-MQ Online ramda Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/grc-ui-rhel8, rhacm2/kui-web-terminal-rhel8 Red Hat Ceph Storage 6.1 Tools rhceph/rhceph-6-rhel9 6-177, rhceph/keepalived-rhel9 2.2.4-3, rhceph/snmp-notifier-rhel9 1.2.1-36, rhceph/rhceph-haproxy-rhel9 2.4.17-4, rhceph/rhceph-promtail-rhel9 v2.4.0-5 Red Hat Enterprise Linux 8 grafana, grafana-loki, grafana-mssql, grafana-mysql, grafana-selinux, grafana-graphite, +8 more Red Hat Enterprise Linux 9 grafana, grafana-selinux
    +1 more products
    Red Hat Openshift Data Foundation 4 odf4/odf-console-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.39% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • jsfiddle.net https://jsfiddle.net/3pomzw5g/2/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:N/I:P/A:P

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype 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.