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Fencer Vulns
medium 6.8

CVE-2021-25220 json

DNS forwarders - cache poisoning vulnerability

published 2022-03-23 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-12131

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.5%
EPSS 3.5% chance of exploitation in 30 days, percentile 89%
public exploits
0
none known

Summary

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.

Patch / fix

  • isc bind 9.11.37, 9.16.27
  • siemens sinec_ins 1.0
  • juniper junos 19.3
  • bind9 Debian 14, Debian 13, Debian 12 1:9.18.1-1

debian advisories DEBIAN-CVE-2021-25220

  • bind9 Ubuntu 18.04 LTS 1:9.11.3+dfsg-1ubuntu1.17
  • bind9 Ubuntu 20.04 LTS 1:9.16.1-0ubuntu2.10
  • bind9 Ubuntu 22.04 LTS 1:9.18.0-2ubuntu3
  • bind9 Ubuntu Pro 14.04 LTS 1:9.9.5.dfsg-3ubuntu0.19+esm6
  • bind9 Ubuntu Pro 16.04 LTS 1:9.10.3.dfsg.P4-8ubuntu1.19+esm2

ubuntu advisories UBUNTU-CVE-2021-25220

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • bind RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-sdb RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-libs RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-utils RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-chroot RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-pkcs11 RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-license RHEL 7 32:9.11.4-26.P2.el7_9.13
  • bind-libs-lite RHEL 7 32:9.11.4-26.P2.el7_9.13

red hat advisories RHSA-2025:23414RHSA-2025:22168RHSA-2025:21889RHSA-2025:21740RHSA-2025:21741RHSA-2024:2720

  • bind SLE Module for Server Applications 15 SP4, SLE Module for Basesystem 15 SP4, openSUSE Leap 15.4 9.16.31-150400.5.6.1
  • bind SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 9.9.9P1-63.34.1
  • bind SLES for SAP 15 SP2, SLES for SAP 15 SP1, SLES for SAP 15 +17 more 9.16.6-150000.12.60.1
  • bind SLE Module for Server Applications 15 SP3, SLE Module for Basesystem 15 SP3 9.16.6-150300.22.16.1
  • bind SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +4 more 9.11.22-3.40.1

suse advisories SUSE-SU-2022:2713-1SUSE-SU-2022:1616-1SUSE-SU-2022:0946-1SUSE-SU-2022:0945-1SUSE-SU-2022:0908-1

  • bind openSUSE Tumbleweed 9.18.2-1.1
  • bind openSUSE Leap 15.3 9.16.6-150000.12.60.1
  • bind openSUSE Leap 15.3 9.16.6-150300.22.16.1

opensuse advisories openSUSE-SU-2024:12081-1openSUSE-SU-2022:0946-1openSUSE-SU-2022:0945-1

  • bind AlmaLinux 9 32:9.16.23-5.el9_1
  • bind-libs AlmaLinux 9 32:9.16.23-5.el9_1
  • bind-utils AlmaLinux 9 32:9.16.23-5.el9_1
  • bind-chroot AlmaLinux 9 32:9.16.23-5.el9_1
  • bind-license AlmaLinux 9 32:9.16.23-5.el9_1
  • python3-bind AlmaLinux 9 32:9.16.23-5.el9_1
  • bind-dnssec-utils AlmaLinux 9 32:9.16.23-5.el9_1
  • dhcp-relay AlmaLinux 9 12:4.4.2-17.b1.el9

almalinux advisories ALSA-2022:8068ALSA-2022:8385ALSA-2022:7643ALSA-2022:7790

  • dhcp Rocky Linux 9 2:4.4.2-17.b1.el9
  • bind Rocky Linux 9 2:9.16.23-5.el9_1
  • bind Rocky Linux 8 2:9.11.36-5.el8_7.2
  • bind9.16 Rocky Linux 8 2:9.16.23-0.9.el8.1

rocky linux advisories RLSA-2022:8385RLSA-2022:8068RLSA-2022:7790RLSA-2022:7643

  • bind Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 9.16.27-r0

alpine advisories ALPINE-CVE-2021-25220

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

  • bind CBL-Mariner 2.0 9.16.29-1

azure linux advisories AZL-9118

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • bind Arch Linux 9.18.1-1

arch linux advisories AVG-2661

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-2021-25220 updated cvss 6.8

bind: DNS forwarders - cache poisoning vulnerability

  • Red Hat CodeReady Linux Builder (v. 8) bind9.16-libs 9.16.23-0.9.el8.1, python3-bind9.16 9.16.23-0.9.el8.1, bind9.16-dnssec-utils 9.16.23-0.9.el8.1
    fixed: vendor fix RHSA-2022:7643
  • Red Hat CodeReady Linux Builder (v. 9) bind-libs 9.16.23-5.el9_1
    fixed: vendor fix RHSA-2022:8068
  • Red Hat Enterprise Linux AppStream (v. 8) bind 9.11.36-5.el8, bind-sdb 9.11.36-5.el8, bind-libs 9.11.36-5.el8, bind-utils 9.11.36-5.el8, bind-chroot 9.11.36-5.el8, bind-pkcs11 9.11.36-5.el8, +11 more
    fixed: vendor fix RHSA-2022:7790
  • Red Hat Enterprise Linux AppStream (v. 9) bind 9.16.23-5.el9_1, bind-libs 9.16.23-5.el9_1, bind-utils 9.16.23-5.el9_1, bind-chroot 9.16.23-5.el9_1, bind-license 9.16.23-5.el9_1, python3-bind 9.16.23-5.el9_1, +1 more
    fixed: vendor fix RHSA-2022:8068
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) bind 9.11.13-6.el8_2.11, bind-sdb 9.11.13-6.el8_2.11, bind-libs 9.11.13-6.el8_2.11, bind-utils 9.11.13-6.el8_2.11, bind-chroot 9.11.13-6.el8_2.11, bind-pkcs11 9.11.13-6.el8_2.11, +6 more
    fixed: vendor fix RHSA-2025:21741
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) bind 9.11.26-4.el8_4.8, bind-sdb 9.11.26-4.el8_4.8, bind-libs 9.11.26-4.el8_4.8, bind-utils 9.11.26-4.el8_4.8, bind-chroot 9.11.26-4.el8_4.8, bind-pkcs11 9.11.26-4.el8_4.8, +6 more
    fixed: vendor fix RHSA-2025:21740
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) bind9.16 9.16.23-0.7.el8_6.9, bind9.16-libs 9.16.23-0.7.el8_6.9, bind9.16-utils 9.16.23-0.7.el8_6.9, bind9.16-chroot 9.16.23-0.7.el8_6.9, bind9.16-license 9.16.23-0.7.el8_6.9 Red Hat Enterprise Linux AppStream E4S (v.8.6) bind9.16 9.16.23-0.7.el8_6.9, bind9.16-libs 9.16.23-0.7.el8_6.9, bind9.16-utils 9.16.23-0.7.el8_6.9, bind9.16-chroot 9.16.23-0.7.el8_6.9, bind9.16-license 9.16.23-0.7.el8_6.9
    fixed: vendor fix RHSA-2025:22168
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) bind 9.16.23-1.el9_0.11, bind-libs 9.16.23-1.el9_0.11, bind-utils 9.16.23-1.el9_0.11, bind-chroot 9.16.23-1.el9_0.11, bind-license 9.16.23-1.el9_0.11, python3-bind 9.16.23-1.el9_0.11, +1 more
    fixed: vendor fix RHSA-2025:21889
show 15 more
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) bind 9.11.36-3.el8_6.7, bind-sdb 9.11.36-3.el8_6.7, bind-libs 9.11.36-3.el8_6.7, bind-utils 9.11.36-3.el8_6.7, bind-chroot 9.11.36-3.el8_6.7, bind-pkcs11 9.11.36-3.el8_6.7, +6 more
    fixed: vendor fix RHSA-2024:2720
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) bind 9.11.26-4.el8_4.8, bind-sdb 9.11.26-4.el8_4.8, bind-libs 9.11.26-4.el8_4.8, bind-utils 9.11.26-4.el8_4.8, bind-chroot 9.11.26-4.el8_4.8, bind-pkcs11 9.11.26-4.el8_4.8, +6 more
    fixed: vendor fix RHSA-2025:21740
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) bind9.16 9.16.23-0.7.el8_6.9, bind9.16-libs 9.16.23-0.7.el8_6.9, bind9.16-utils 9.16.23-0.7.el8_6.9, bind9.16-chroot 9.16.23-0.7.el8_6.9, bind9.16-license 9.16.23-0.7.el8_6.9
    fixed: vendor fix RHSA-2025:22168
  • Red Hat Enterprise Linux BaseOS (v. 8) bind 9.11.36-5.el8, bind-export-libs 9.11.36-5.el8
    fixed: vendor fix RHSA-2022:7790
  • Red Hat Enterprise Linux BaseOS (v. 9) dhcp 4.4.2-17.b1.el9, dhcp-relay 4.4.2-17.b1.el9, dhcp-client 4.4.2-17.b1.el9, dhcp-common 4.4.2-17.b1.el9, dhcp-server 4.4.2-17.b1.el9
    fixed: vendor fix RHSA-2022:8385
  • Red Hat Enterprise Linux BaseOS AUS (v. 8.2) bind 9.11.13-6.el8_2.11, bind-export-libs 9.11.13-6.el8_2.11
    fixed: vendor fix RHSA-2025:21741
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bind 9.11.26-4.el8_4.8, bind-export-libs 9.11.26-4.el8_4.8
    fixed: vendor fix RHSA-2025:21740
  • Red Hat Enterprise Linux BaseOS EUS (v.8.6) dhcp 4.3.6-47.el8_6.2, bind 9.11.36-3.el8_6.7, dhcp-libs 4.3.6-47.el8_6.2, dhcp-relay 4.3.6-47.el8_6.2, dhcp-client 4.3.6-47.el8_6.2, dhcp-common 4.3.6-47.el8_6.2, +2 more
    fixed: vendor fix RHSA-2024:2720
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bind 9.11.26-4.el8_4.8, bind-export-libs 9.11.26-4.el8_4.8
    fixed: vendor fix RHSA-2025:21740
  • Red Hat Enterprise Linux Client (v. 7) bind 9.11.4-26.P2.el7_9.13, bind-libs 9.11.4-26.P2.el7_9.13, bind-utils 9.11.4-26.P2.el7_9.13, bind-license 9.11.4-26.P2.el7_9.13, bind-libs-lite 9.11.4-26.P2.el7_9.13, bind-export-libs 9.11.4-26.P2.el7_9.13 Red Hat Enterprise Linux Client Optional (v. 7) bind 9.11.4-26.P2.el7_9.13, bind-sdb 9.11.4-26.P2.el7_9.13, bind-chroot 9.11.4-26.P2.el7_9.13, bind-pkcs11 9.11.4-26.P2.el7_9.13, bind-sdb-chroot 9.11.4-26.P2.el7_9.13, bind-pkcs11-libs 9.11.4-26.P2.el7_9.13, +1 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) bind 9.11.4-26.P2.el7_9.13, bind-sdb 9.11.4-26.P2.el7_9.13, bind-chroot 9.11.4-26.P2.el7_9.13, bind-pkcs11 9.11.4-26.P2.el7_9.13, bind-sdb-chroot 9.11.4-26.P2.el7_9.13, bind-pkcs11-libs 9.11.4-26.P2.el7_9.13, +1 more
    fixed: vendor fix RHSA-2023:0402
  • Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION) bind 9.8.2-0.68.rc1.el6_10.17, bind-libs 9.8.2-0.68.rc1.el6_10.17, bind-utils 9.8.2-0.68.rc1.el6_10.17
    fixed: vendor fix RHSA-2025:23414
  • Red Hat Enterprise Linux Server (v. 7) bind 9.11.4-26.P2.el7_9.13, bind-libs 9.11.4-26.P2.el7_9.13, bind-utils 9.11.4-26.P2.el7_9.13, bind-chroot 9.11.4-26.P2.el7_9.13, bind-pkcs11 9.11.4-26.P2.el7_9.13, bind-license 9.11.4-26.P2.el7_9.13, +4 more
    fixed: vendor fix RHSA-2023:0402
  • Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) bind-sdb 9.8.2-0.68.rc1.el6_10.17
    fixed: vendor fix RHSA-2025:23414
  • Red Hat Enterprise Linux Server Optional (v. 7) bind-sdb 9.11.4-26.P2.el7_9.13, bind-sdb-chroot 9.11.4-26.P2.el7_9.13 Red Hat Enterprise Linux Workstation (v. 7) bind 9.11.4-26.P2.el7_9.13, bind-libs 9.11.4-26.P2.el7_9.13, bind-utils 9.11.4-26.P2.el7_9.13, bind-chroot 9.11.4-26.P2.el7_9.13, bind-pkcs11 9.11.4-26.P2.el7_9.13, bind-license 9.11.4-26.P2.el7_9.13, +4 more Red Hat Enterprise Linux Workstation Optional (v. 7) bind-sdb 9.11.4-26.P2.el7_9.13, bind-sdb-chroot 9.11.4-26.P2.el7_9.13
    fixed: vendor fix RHSA-2023:0402
  • Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION) bind 9.8.2-0.68.rc1.el6_10.17, bind-chroot 9.8.2-0.68.rc1.el6_10.17 Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) bind-devel 9.8.2-0.68.rc1.el6_10.17, bind-debuginfo 9.8.2-0.68.rc1.el6_10.17
    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

cisa ICSA-25-105-08 updated cvss 6.8

ABB M2M Gateway

  • ABB M2M Gateway >=4.1.2, <=5.0.3, >=5.0.1, <=5.0.3
    affected: mitigation

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

3.45% chance of exploitation in the next 30 days, higher than 89% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N

Affected products

  • ISC BIND

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

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.