No exploitation reportedFix available

CVE-2021-3504

No exploitation reported by the sources we read.

Published2021-05-11
WeaknessCWE-125

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw was found in the hivex library in versions before 1.3.20. It is caused due to a lack of bounds check within the hivex_open function. An attacker could input a specially crafted Windows Registry (hive) file which would cause hivex to read memory beyond its normal bounds or cause the program to crash. The highest threat from this vulnerability is to system availability.

Timeline

dates in UTC

2021-05-1123:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-3504?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-3504?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Redhat enterprise linux

Branch	Affected	Fixed in	Source
6.0	= 6.0	no fix published	NVD
7.0	= 7.0	no fix published	NVD
8.0	= 8.0	no fix published	NVD

Debian debian linux

Branch	Affected	Fixed in	Source
9.0	= 9.0	no fix published	NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
34.x	= 34	no fix published	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

libguestfs-winsupportAlmaLinux:8all versions · fixed in 8.2-1.module_el8.5.0+2608+72063365
libiscsiAlmaLinux:8all versions · fixed in 1.18.0-8.module_el8.5.0+2608+72063365and 2 other packages
libiscsiAlmaLinux:8all versions · fixed in 1.18.0-8.module_el8.6.0+2880+7d9e3703and 2 other packages
libnbdAlmaLinux:8all versions · fixed in 1.2.2-1.module_el8.5.0+2608+72063365and 3 other packages
libvirt-dbusAlmaLinux:8all versions · fixed in 1.3.0-2.module_el8.5.0+2608+72063365
libvirt-dbusAlmaLinux:8all versions · fixed in 1.3.0-2.module_el8.6.0+2880+7d9e3703
nbdkitAlmaLinux:8all versions · fixed in 1.16.2-4.module_el8.5.0+2608+72063365and 13 other packages
netcfAlmaLinux:8all versions · fixed in 0.2.8-12.module_el8.5.0+2608+72063365and 2 other packages

6 more package ranges on OSV.dev

Full record on NVD

Fix

Advisories and patches

bugzilla.redhat.comPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.15.4read 2026-10-23
NVDCVSS 2.05.8read 2026-10-23
CNAweakness (CWE)CWE-125read 2026-10-23
FIRST EPSSEPSS score1.9 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
Published: 2021-05-11
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-3504?

Is CVE-2021-3504 actively exploited?

Active exploitation of CVE-2021-3504 has not been confirmed. Its EPSS score was 1.9% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-3504?

CVE-2021-3504 has a CVSS v3 base score of 5.4 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L.

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