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Fencer Intel
medium 6.5

CVE-2021-25214 json

A broken inbound incremental zone update (IXFR) can cause named to terminate unexpectedly

published 5y ago modified 4mo ago also EUVD-2021-12125

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
6.4%
EPSS 6.4% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

In BIND 9.8.5 -> 9.8.8, 9.9.3 -> 9.11.29, 9.12.0 -> 9.16.13, and versions BIND 9.9.3-S1 -> 9.11.29-S1 and 9.16.8-S1 -> 9.16.13-S1 of BIND 9 Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.11 of the BIND 9.17 development branch, when a vulnerable version of named receives a malformed IXFR triggering the flaw described above, the named process will terminate due to a failed assertion the next time the transferred secondary zone is refreshed.

Patch / fix

  • isc bind 9.11.31, 9.16.15, 9.17.12
  • siemens sinec_infrastructure_network_services 1.0.1.1
  • bind9 Debian 14, Debian 13, Debian 12 1:9.16.15-1

debian advisories DEBIAN-CVE-2021-25214

  • bind9 Ubuntu 16.04 LTS 1:9.10.3.dfsg.P4-8ubuntu1.19
  • bind9 Ubuntu 18.04 LTS 1:9.11.3+dfsg-1ubuntu1.15
  • bind9 Ubuntu 20.04 LTS 1:9.16.1-0ubuntu2.8
  • bind9 Ubuntu Pro 14.04 LTS 1:9.9.5.dfsg-3ubuntu0.19+esm13

ubuntu advisories UBUNTU-CVE-2021-25214

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 8 32:9.11.26-6.el8
  • bind-sdb RHEL 8 32:9.11.26-6.el8
  • bind-libs RHEL 8 32:9.11.26-6.el8
  • bind-utils RHEL 8 32:9.11.26-6.el8
  • bind-chroot RHEL 8 32:9.11.26-6.el8
  • bind-pkcs11 RHEL 8 32:9.11.26-6.el8
  • bind-license RHEL 8 32:9.11.26-6.el8
  • python3-bind RHEL 8 32:9.11.26-6.el8

red hat advisories RHSA-2021:4384RHSA-2021:3325

  • bind SLE Module for Server Applications 15 SP3, SLE Module for Basesystem 15 SP3 9.16.6-22.7.1
  • bind SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +12 more 9.16.6-12.49.1
  • bind SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 9.9.6P1-0.51.26.1
  • bind SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 9.9.9P1-63.25.1
  • bind SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +4 more 9.11.22-3.34.1

suse advisories SUSE-SU-2021:1826-1SUSE-SU-2021:1471-1SUSE-SU-2021:14714-1SUSE-SU-2021:1469-1SUSE-SU-2021:1468-1

  • bind openSUSE Tumbleweed 9.16.20-1.4
  • bind openSUSE Leap 15.3 9.16.6-22.7.1
  • bind openSUSE Leap 15.2 9.16.6-lp152.14.19.1

opensuse advisories openSUSE-SU-2024:10650-1openSUSE-SU-2021:1826-1openSUSE-SU-2021:0668-1

  • bind AlmaLinux 8 32:9.11.26-6.el8
  • bind-sdb AlmaLinux 8 32:9.11.26-6.el8
  • bind-libs AlmaLinux 8 32:9.11.26-6.el8
  • bind-utils AlmaLinux 8 32:9.11.26-6.el8
  • bind-chroot AlmaLinux 8 32:9.11.26-6.el8
  • bind-pkcs11 AlmaLinux 8 32:9.11.26-6.el8
  • bind-license AlmaLinux 8 32:9.11.26-6.el8
  • python3-bind AlmaLinux 8 32:9.11.26-6.el8

almalinux advisories ALSA-2021:4384

  • bind Rocky Linux 8 2:9.11.26-6.el8

rocky linux advisories RLSA-2021:4384

  • bind Alpine 3.24, Alpine 3.23, Alpine 3.22 +12 more 9.16.15-r0

alpine advisories ALPINE-CVE-2021-25214

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 Arch Linux 9.16.15-1

arch linux advisories AVG-1890

Is CVE-2021-25214 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2021-25214 updated cvss 6.5

bind: Broken inbound incremental zone update (IXFR) can cause named to terminate unexpectedly

  • Red Hat Enterprise Linux AppStream (v. 8) bind 9.11.26-6.el8, bind-sdb 9.11.26-6.el8, bind-libs 9.11.26-6.el8, bind-utils 9.11.26-6.el8, bind-chroot 9.11.26-6.el8, bind-pkcs11 9.11.26-6.el8, +6 more Red Hat Enterprise Linux BaseOS (v. 8) bind 9.11.26-6.el8, bind-export-libs 9.11.26-6.el8
    fixed: vendor fix “Disabling incremental zone transfers (IXFR) by setting "request-ixfr no;" in the desired configuration block (options, zone, or server) prevents the failing assertion from being evaluated.” RHSA-2021:4384
  • Red Hat Enterprise Linux Client (v. 7) bind 9.11.4-26.P2.el7_9.7, bind-libs 9.11.4-26.P2.el7_9.7, bind-utils 9.11.4-26.P2.el7_9.7, bind-license 9.11.4-26.P2.el7_9.7, bind-libs-lite 9.11.4-26.P2.el7_9.7, bind-export-libs 9.11.4-26.P2.el7_9.7 Red Hat Enterprise Linux Client Optional (v. 7) bind 9.11.4-26.P2.el7_9.7, bind-sdb 9.11.4-26.P2.el7_9.7, bind-chroot 9.11.4-26.P2.el7_9.7, bind-pkcs11 9.11.4-26.P2.el7_9.7, bind-sdb-chroot 9.11.4-26.P2.el7_9.7, bind-pkcs11-libs 9.11.4-26.P2.el7_9.7, +1 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) bind 9.11.4-26.P2.el7_9.7, bind-sdb 9.11.4-26.P2.el7_9.7, bind-chroot 9.11.4-26.P2.el7_9.7, bind-pkcs11 9.11.4-26.P2.el7_9.7, bind-sdb-chroot 9.11.4-26.P2.el7_9.7, bind-pkcs11-libs 9.11.4-26.P2.el7_9.7, +1 more Red Hat Enterprise Linux Server (v. 7) bind 9.11.4-26.P2.el7_9.7, bind-libs 9.11.4-26.P2.el7_9.7, bind-utils 9.11.4-26.P2.el7_9.7, bind-chroot 9.11.4-26.P2.el7_9.7, bind-pkcs11 9.11.4-26.P2.el7_9.7, bind-license 9.11.4-26.P2.el7_9.7, +4 more Red Hat Enterprise Linux Server Optional (v. 7) bind-sdb 9.11.4-26.P2.el7_9.7, bind-sdb-chroot 9.11.4-26.P2.el7_9.7 Red Hat Enterprise Linux Workstation (v. 7) bind 9.11.4-26.P2.el7_9.7, bind-libs 9.11.4-26.P2.el7_9.7, bind-utils 9.11.4-26.P2.el7_9.7, bind-chroot 9.11.4-26.P2.el7_9.7, bind-pkcs11 9.11.4-26.P2.el7_9.7, bind-license 9.11.4-26.P2.el7_9.7, +4 more
    +1 more products
    Red Hat Enterprise Linux Workstation Optional (v. 7) bind-sdb 9.11.4-26.P2.el7_9.7, bind-sdb-chroot 9.11.4-26.P2.el7_9.7
    fixed: vendor fix “Disabling incremental zone transfers (IXFR) by setting "request-ixfr no;" in the desired configuration block (options, zone, or server) prevents the failing assertion from being evaluated.” RHSA-2021:3325
  • Red Hat Enterprise Linux 5 bind, bind97 Red Hat Enterprise Linux 6 bind, bind-sdb, bind-libs, bind-utils, bind-chroot Red Hat Enterprise Linux 9 bind, bind-libs, bind-utils, bind-chroot, bind-license, python3-bind, +1 more
    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

Exploit prediction

6.40% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • ISC BIND9

Classification

Weakness

References

Sources

Fencer Intel 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.