synced 5 MIN AGO
01 Record

CVE-2021-25220

DNS forwarders - cache poisoning vulnerability

MediumPUBLISHEDCNA: isc
CNA base score6.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N
View raw JSON

02 Description

DNS forwarders - cache poisoning vulnerability

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
3.45% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 88.9% of scored records. A rank, not a probability.
NVD base score
6.8 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2022-03-23 12:50Z4 YR AGO
Last updated
2024-09-16 17:08Z2 YR AGO
Reserved
2021-01-15
Assigning CNA
isc
Record state
PUBLISHED
Severity
Medium (CVSS 6.8)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N
Weaknesses
  • CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')Base
Data version
5.1
Document digest
468079ffa4c7e9d712f2e1c0698c40b8f4217c7fd819ad9be31393aca6665469

05 Affected products

VendorProductVersionsPlatforms
ISCBINDOpen Source Branch 9.11 9.11.0 through versions before 9.11.37, Development Branch 9.17 BIND 9.17 all version, Open Source Branch 9.12-16 9.12.0 through versions before 9.16.27, Open Source Branch 9.18 9.18.0, Supported Preview Branch 9.11-S 9.11.0-S through versions before 9.11.37-S, Supported Preview Branch 9.16-S 9.16.0-S through versions before 9.16.27-S—

06 References

07 Remediation

Upgrade to the patched release most closely related to your current version of BIND: BIND 9.11.37 BIND 9.16.27 BIND 9.18.1 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. BIND 9.11.37-S1 BIND 9.16.27-S1

08 Fixed in

AlmaLinux 8

  • bind
    Fixed in 32:9.11.36-5.el8
  • bind-chroot
    Fixed in 32:9.11.36-5.el8
  • bind-devel
    Fixed in 32:9.11.36-5.el8
  • bind-export-devel
    Fixed in 32:9.11.36-5.el8
  • bind-export-libs
    Fixed in 32:9.11.36-5.el8
  • bind-libs
    Fixed in 32:9.11.36-5.el8
  • bind-libs-lite
    Fixed in 32:9.11.36-5.el8
  • bind-license
    Fixed in 32:9.11.36-5.el8
  • bind-lite-devel
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11-devel
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11-libs
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11-utils
    Fixed in 32:9.11.36-5.el8
  • bind-sdb
    Fixed in 32:9.11.36-5.el8
  • bind-sdb-chroot
    Fixed in 32:9.11.36-5.el8
  • bind-utils
    Fixed in 32:9.11.36-5.el8
  • bind9.16
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-chroot
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-devel
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-dnssec-utils
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-doc
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-libs
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-license
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-utils
    Fixed in 32:9.16.23-0.9.el8.1
  • python3-bind
    Fixed in 32:9.11.36-5.el8
  • python3-bind9.16
    Fixed in 32:9.16.23-0.9.el8.1

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 9

  • bind
    Fixed in 32:9.16.23-5.el9_1
  • bind-chroot
    Fixed in 32:9.16.23-5.el9_1
  • bind-devel
    Fixed in 32:9.16.23-5.el9_1
  • bind-dnssec-doc
    Fixed in 32:9.16.23-5.el9_1
  • bind-dnssec-utils
    Fixed in 32:9.16.23-5.el9_1
  • bind-doc
    Fixed in 32:9.16.23-5.el9_1
  • bind-libs
    Fixed in 32:9.16.23-5.el9_1
  • bind-license
    Fixed in 32:9.16.23-5.el9_1
  • bind-utils
    Fixed in 32:9.16.23-5.el9_1
  • dhcp-client
    Fixed in 12:4.4.2-17.b1.el9
  • dhcp-common
    Fixed in 12:4.4.2-17.b1.el9
  • dhcp-relay
    Fixed in 12:4.4.2-17.b1.el9
  • dhcp-server
    Fixed in 12:4.4.2-17.b1.el9
  • python3-bind
    Fixed in 32:9.16.23-5.el9_1

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Arch Linux

  • bind
    Fixed in 9.18.1-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

CloudLinux 8

  • bind
    Fixed in 32:9.11.36-5.el8
  • bind-chroot
    Fixed in 32:9.11.36-5.el8
  • bind-devel
    Fixed in 32:9.11.36-5.el8
  • bind-export-devel
    Fixed in 32:9.11.36-5.el8
  • bind-export-libs
    Fixed in 32:9.11.36-5.el8
  • bind-libs
    Fixed in 32:9.11.36-5.el8
  • bind-libs-lite
    Fixed in 32:9.11.36-5.el8
  • bind-license
    Fixed in 32:9.11.36-5.el8
  • bind-lite-devel
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11-devel
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11-libs
    Fixed in 32:9.11.36-5.el8
  • bind-pkcs11-utils
    Fixed in 32:9.11.36-5.el8
  • bind-sdb
    Fixed in 32:9.11.36-5.el8
  • bind-sdb-chroot
    Fixed in 32:9.11.36-5.el8
  • bind-utils
    Fixed in 32:9.11.36-5.el8
  • bind9.16
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-chroot
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-devel
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-dnssec-utils
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-doc
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-libs
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-license
    Fixed in 32:9.16.23-0.9.el8.1
  • bind9.16-utils
    Fixed in 32:9.16.23-0.9.el8.1
  • python3-bind
    Fixed in 32:9.11.36-5.el8
  • python3-bind9.16
    Fixed in 32:9.16.23-0.9.el8.1

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 9

  • bind
    Fixed in 32:9.16.23-5.el9_1
  • bind-chroot
    Fixed in 32:9.16.23-5.el9_1
  • bind-devel
    Fixed in 32:9.16.23-5.el9_1
  • bind-dnssec-doc
    Fixed in 32:9.16.23-5.el9_1
  • bind-dnssec-utils
    Fixed in 32:9.16.23-5.el9_1
  • bind-doc
    Fixed in 32:9.16.23-5.el9_1
  • bind-libs
    Fixed in 32:9.16.23-5.el9_1
  • bind-license
    Fixed in 32:9.16.23-5.el9_1
  • bind-utils
    Fixed in 32:9.16.23-5.el9_1
  • dhcp-client
    Fixed in 12:4.4.2-17.b1.el9
  • dhcp-common
    Fixed in 12:4.4.2-17.b1.el9
  • dhcp-relay
    Fixed in 12:4.4.2-17.b1.el9
  • dhcp-server
    Fixed in 12:4.4.2-17.b1.el9
  • python3-bind
    Fixed in 32:9.16.23-5.el9_1

Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • bind9
    Fixed in 1:9.18.1-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • bind9
    Fixed in 1:9.18.1-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • bind9
    Fixed in 1:9.18.1-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • bind9
    Fixed in 1:9.11.3+dfsg-1ubuntu1.17

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • bind9
    Fixed in 1:9.16.1-0ubuntu2.10

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • bind9
    Fixed in 1:9.18.0-2ubuntu3

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 14.04 LTS

  • bind9
    Fixed in 1:9.9.5.dfsg-3ubuntu0.19+esm6
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 16.04 LTS

  • bind9
    Fixed in 1:9.10.3.dfsg.P4-8ubuntu1.19+esm2
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.