CVE-2021-25220

MEDIUMEPSS 88th pctl

6.8

CVSS v3

Description

BIND 9.11.0 -> 9.11.36 9.12.0 -> 9.16.26 9.17.0 -> 9.18.0 BIND Supported Preview Editions: 9.11.4-S1 -> 9.11.36-S1 9.16.8-S1 -> 9.16.26-S1 Versions of BIND 9 earlier than those shown - back to 9.1.0, including Supported Preview Editions - are also believed to be affected but have not been tested as they are EOL. The cache could become poisoned with incorrect records leading to queries being made to the wrong servers, which might also result in false information being returned to clients.

CWE-444

How to fix

Remediation Available

bind9Debian

Fixed in:1:9.16.27-1~deb11u1CVE-2021-25220

Fixed in:1:9.18.1-1CVE-2021-25220

bindRocky

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

bindRed Hat / RHEL

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

bind-chrootRocky

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-chrootRed Hat / RHEL

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-debuginfoRocky

Fixed in:32:9.8.2-0.68.rc1.el6_10.17.s390RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-debuginfoRed Hat / RHEL

Fixed in:32:9.8.2-0.68.rc1.el6_10.17.s390RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

bind-debugsourceRocky

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

bind-debugsourceRed Hat / RHEL

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-develRed Hat / RHEL

Fixed in:32:9.8.2-0.68.rc1.el6_10.17.s390RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

bind-develRocky

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17.s390RHSA-2025:23414

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-dnssec-docRocky

Fixed in:32:9.16.23-1.el9_0.11RHSA-2025:21889

bind-dnssec-docRed Hat / RHEL

Fixed in:32:9.16.23-1.el9_0.11RHSA-2025:21889

bind-dnssec-utilsRocky

Fixed in:32:9.16.23-1.el9_0.11RHSA-2025:21889

bind-dnssec-utilsRed Hat / RHEL

Fixed in:32:9.16.23-1.el9_0.11RHSA-2025:21889

bind-dnssec-utils-debuginfoRed Hat / RHEL

Fixed in:32:9.16.23-1.el9_0.11RHSA-2025:21889

bind-dnssec-utils-debuginfoRocky

Fixed in:32:9.16.23-1.el9_0.11RHSA-2025:21889

bind-export-develRocky

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-export-develRed Hat / RHEL

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-export-libsRed Hat / RHEL

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

bind-export-libsRocky

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

bind-export-libs-debuginfoRocky

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-export-libs-debuginfoRed Hat / RHEL

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-libsRocky

Fixed in:32:9.8.2-0.68.rc1.el6_10.17.s390RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-libsRed Hat / RHEL

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17.s390RHSA-2025:23414

Fixed in:32:9.8.2-0.68.rc1.el6_10.17RHSA-2025:23414

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

bind-libs-debuginfoRed Hat / RHEL

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

bind-libs-debuginfoRocky

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

bind-libs-liteRed Hat / RHEL

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

bind-libs-liteRocky

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

bind-libs-lite-debuginfoRed Hat / RHEL

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.26-4.el8_4.8RHSA-2025:21740

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

Fixed in:32:9.11.36-3.el8_6.7RHSA-2024:2720

Fixed in:32:9.11.13-6.el8_2.11RHSA-2025:21741

This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N

Exploit Intelligence

3.36%probability of exploitation in 30 days

88thpercentile

Elevated risk: more likely to be exploited than 88% of all known CVEs.

References

Patch1

cert-portal.siemens.com

Vendor Advisory1

kb.isc.org

Third-Party Advisory2

Other references6

Related Vulnerabilities

Other CWE-444 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-22536	Critical	10.0	98%	KEV	-
CVE-2025-61884	High	7.5	98%	KEV + Ransom	-
CVE-2020-9490	High	7.5	89%	-	Fix
CVE-2023-41265	Critical	9.6	88%	KEV + Ransom	-
CVE-2023-25690	Critical	9.8	85%	-	Fix
CVE-2022-32214	Medium	6.5	81%	-	Fix

Common questions

How do I fix CVE-2021-25220?

Published advisories record a fix for 106 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2021-25220 being actively exploited?

Not that we know of. CVE-2021-25220 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 3.4% is the estimated probability that it will be exploited in the next 30 days. That is higher than 88% of all scored CVEs.

How severe is CVE-2021-25220?

CVE-2021-25220 has a CVSS v3 base score of 6.8, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-25220 affect?

Published advisories record a fix for bind9 (Debian), bind (Rocky), bind (Red Hat / RHEL), bind-chroot (Rocky), and 102 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2021-25220

Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.