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CVE Vulnerability Details :
CVE-2026-4891
PUBLISHED
More InfoOfficial Page
Assigner-certcc
Assigner Org ID-37e5125f-f79b-445b-8fad-9564f167944b
View Known Exploited Vulnerability (KEV) details
Published At-11 May, 2026 | 16:47
Updated At-03 Jul, 2026 | 12:05
Rejected At-
▼CVE Numbering Authority (CNA)
CVE-2026-4891

A heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

Affected Products
Vendor
dnsmasq
Product
dnsmasq
Versions
Affected
  • From 0 before 2.92rel2 (custom)
Problem Types
TypeCWE IDDescription
N/AN/ACWE-125: Out-of-bounds Read
Type: N/A
CWE ID: N/A
Description: CWE-125: Out-of-bounds Read
Metrics
VersionBase scoreBase severityVector
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Configurations

Workarounds

Exploits

Credits

Timeline
EventDate
Replaced By

Rejected Reason

References
HyperlinkResource
https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2026q2/018471.html
N/A
https://www.kb.cert.org/vuls/id/471747
N/A
https://thekelleys.org.uk/dnsmasq/CVE/
N/A
https://github.com/NixOS/nixpkgs/pull/519082
N/A
https://github.com/NixOS/nixpkgs/pull/519093
N/A
https://github.com/pi-hole/FTL/releases/tag/v6.6.2
N/A
Hyperlink: https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2026q2/018471.html
Resource: N/A
Hyperlink: https://www.kb.cert.org/vuls/id/471747
Resource: N/A
Hyperlink: https://thekelleys.org.uk/dnsmasq/CVE/
Resource: N/A
Hyperlink: https://github.com/NixOS/nixpkgs/pull/519082
Resource: N/A
Hyperlink: https://github.com/NixOS/nixpkgs/pull/519093
Resource: N/A
Hyperlink: https://github.com/pi-hole/FTL/releases/tag/v6.6.2
Resource: N/A
▼Authorized Data Publishers (ADP)
1. CISA ADP Vulnrichment
Affected Products
Metrics
VersionBase scoreBase severityVector
3.15.3MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Version: 3.1
Base score: 5.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Configurations

Workarounds

Exploits

Credits

Timeline
EventDate
Replaced By

Rejected Reason

References
HyperlinkResource
2. dnsmasq: RRSIG rdlen underflow leading to heap OOB read

A heap out-of-bounds read vulnerability was discovered in dnsmasq's DNSSEC validation. When processing RRSIG records, dnsmasq calculates the signature length by subtracting the fixed field size from the record's declared data length. A crafted RRSIG record with a data length smaller than the fixed fields causes this calculation to underflow, potentially resulting in an out-of-bounds read and process crash.

Affected Products
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat Enterprise Linux AppStream (v. 10)
CPEs
  • cpe:/o:redhat:enterprise_linux:10.2
Default Status
affected
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat Enterprise Linux AppStream (v. 8)
CPEs
  • cpe:/a:redhat:enterprise_linux:8::appstream
Default Status
affected
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat Enterprise Linux AppStream EUS (v.9.6)
CPEs
  • cpe:/a:redhat:rhel_eus:9.6::appstream
Default Status
affected
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat Enterprise Linux AppStream (v. 9)
CPEs
  • cpe:/a:redhat:enterprise_linux:9::appstream
Default Status
affected
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat Enterprise Linux 6
CPEs
  • cpe:/o:redhat:enterprise_linux:6
Default Status
affected
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat Enterprise Linux 7
CPEs
  • cpe:/o:redhat:enterprise_linux:7
Default Status
affected
Vendor
Red Hat, Inc.Red Hat
Product
Red Hat OpenShift Container Platform 4
CPEs
  • cpe:/a:redhat:openshift:4
Default Status
affected
Problem Types
TypeCWE IDDescription
CWECWE-125Out-of-bounds Read
Type: CWE
CWE ID: CWE-125
Description: Out-of-bounds Read
Metrics
VersionBase scoreBase severityVector
3.17.5HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Version: 3.1
Base score: 7.5
Base severity: HIGH
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Metrics Other Info
Red Hat severity rating
value:
Important
namespace:
https://access.redhat.com/security/updates/classification/
Impacts
CAPEC IDDescription
Solutions

RHSA-2026:19158: Red Hat Enterprise Linux AppStream (v. 10)

RHSA-2026:20589: Red Hat Enterprise Linux AppStream (v. 8)

RHSA-2026:34508: Red Hat Enterprise Linux AppStream EUS (v.9.6)

RHSA-2026:19373: Red Hat Enterprise Linux AppStream (v. 9)

Configurations

Workarounds

Exploits

Credits

Timeline
EventDate
Reported to Red Hat.2026-04-14 22:39:35
Made public.2026-05-09 00:00:00
Event: Reported to Red Hat.
Date: 2026-04-14 22:39:35
Event: Made public.
Date: 2026-05-09 00:00:00
Replaced By

Rejected Reason

References
HyperlinkResource
https://access.redhat.com/security/cve/CVE-2026-4891
vdb-entry
x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2458517
issue-tracking
x_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4891.json
x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:19158
vendor-advisory
x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:20589
vendor-advisory
x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:34508
vendor-advisory
x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:19373
vendor-advisory
x_refsource_REDHAT
Hyperlink: https://access.redhat.com/security/cve/CVE-2026-4891
Resource:
vdb-entry
x_refsource_REDHAT
Hyperlink: https://bugzilla.redhat.com/show_bug.cgi?id=2458517
Resource:
issue-tracking
x_refsource_REDHAT
Hyperlink: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4891.json
Resource:
x_sadp-csaf-vex
Hyperlink: https://access.redhat.com/errata/RHSA-2026:19158
Resource:
vendor-advisory
x_refsource_REDHAT
Hyperlink: https://access.redhat.com/errata/RHSA-2026:20589
Resource:
vendor-advisory
x_refsource_REDHAT
Hyperlink: https://access.redhat.com/errata/RHSA-2026:34508
Resource:
vendor-advisory
x_refsource_REDHAT
Hyperlink: https://access.redhat.com/errata/RHSA-2026:19373
Resource:
vendor-advisory
x_refsource_REDHAT
Details not found