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Fencer Vulns
high 7.5

CVE-2021-34555 json

OpenDMARC 1.4.1 and 1.4.1.1 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a mul…

published 2021-06-10 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21205

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.6%
EPSS 2.6% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

OpenDMARC 1.4.1 and 1.4.1.1 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a multi-value From header field.

Patch / fix

  • opendmarc Debian 14, Debian 13, Debian 12 1.4.0~beta1+dfsg-6

debian advisories DEBIAN-CVE-2021-34555

  • opendmarc Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 1.4.1.1-r3

alpine advisories ALPINE-CVE-2021-34555

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2021-34555 updated cvss 7.5

opendmarc: remote NULL pointer dereference may lead to a DoS

  • Red Hat All currently supported Red Hat products
    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

2.57% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/trusteddomainproject/OpenDMARC/issues/179 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

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.