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Fencer Vulns
high 7.5

CVE-2021-25215 in the critical feed json

An assertion check can fail while answering queries for DNAME records that require the DNAME to be processed to resolve itself

published 2021-04-29 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-12126

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
11.7%
EPSS 11.7% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

In BIND 9.0.0 -> 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 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 query for a record triggering the flaw described above, the named process will terminate due to a failed assertion check. The vulnerability affects all currently maintained BIND 9 branches (9.11, 9.11-S, 9.16, 9.16-S, 9.17) as well as all other versions of BIND 9.

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-2021-25215

  • 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-2021-25215

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 32:9.11.26-4.el8_4
  • bind-sdb RHEL 8 32:9.11.26-4.el8_4
  • bind-libs RHEL 8 32:9.11.26-4.el8_4
  • bind-utils RHEL 8 32:9.11.26-4.el8_4
  • bind-chroot RHEL 8 32:9.11.26-4.el8_4
  • bind-pkcs11 RHEL 8 32:9.11.26-4.el8_4
  • bind-license RHEL 8 32:9.11.26-4.el8_4
  • python3-bind RHEL 8 32:9.11.26-4.el8_4

red hat advisories RHSA-2021:2024RHSA-2021:2028RHSA-2021:1989RHSA-2021:1479RHSA-2021:1478RHSA-2021:1477

  • 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 Rocky Linux 8 2:9.11.26-4.el8_4

rocky linux advisories RLSA-2021:1989

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

alpine advisories ALPINE-CVE-2021-25215

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

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-2021-25215 updated cvss 7.5

bind: An assertion check can fail while answering queries for DNAME records that require the DNAME to be processed to resolve itself

  • Red Hat Enterprise Linux 5 bind, bind97
    affected: workaround, no fix planned “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.”
  • Red Hat Enterprise Linux AppStream (v. 8) bind 9.11.26-4.el8_4, bind-sdb 9.11.26-4.el8_4, bind-libs 9.11.26-4.el8_4, bind-utils 9.11.26-4.el8_4, bind-chroot 9.11.26-4.el8_4, bind-pkcs11 9.11.26-4.el8_4, +6 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1989
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) bind 9.11.4-26.P2.el8_1.5, bind-sdb 9.11.4-26.P2.el8_1.5, bind-libs 9.11.4-26.P2.el8_1.5, bind-utils 9.11.4-26.P2.el8_1.5, bind-chroot 9.11.4-26.P2.el8_1.5, bind-pkcs11 9.11.4-26.P2.el8_1.5, +6 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:2028
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) bind 9.11.13-6.el8_2.3, bind-sdb 9.11.13-6.el8_2.3, bind-libs 9.11.13-6.el8_2.3, bind-utils 9.11.13-6.el8_2.3, bind-chroot 9.11.13-6.el8_2.3, bind-pkcs11 9.11.13-6.el8_2.3, +6 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:2024
  • Red Hat Enterprise Linux BaseOS (v. 8) bind 9.11.26-4.el8_4, bind-export-libs 9.11.26-4.el8_4
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1989
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.1) bind 9.11.4-26.P2.el8_1.5, bind-export-libs 9.11.4-26.P2.el8_1.5
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:2028
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) bind 9.11.13-6.el8_2.3, bind-export-libs 9.11.13-6.el8_2.3
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:2024
  • Red Hat Enterprise Linux Client (v. 7) bind 9.11.4-26.P2.el7_9.5, bind-libs 9.11.4-26.P2.el7_9.5, bind-utils 9.11.4-26.P2.el7_9.5, bind-license 9.11.4-26.P2.el7_9.5, bind-libs-lite 9.11.4-26.P2.el7_9.5, bind-export-libs 9.11.4-26.P2.el7_9.5 Red Hat Enterprise Linux Client Optional (v. 7) bind 9.11.4-26.P2.el7_9.5, bind-sdb 9.11.4-26.P2.el7_9.5, bind-chroot 9.11.4-26.P2.el7_9.5, bind-pkcs11 9.11.4-26.P2.el7_9.5, bind-sdb-chroot 9.11.4-26.P2.el7_9.5, bind-pkcs11-libs 9.11.4-26.P2.el7_9.5, +1 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1469
show 23 more
  • Red Hat Enterprise Linux ComputeNode EUS (v. 7.6) bind 9.9.4-74.el7_6.7, bind-libs 9.9.4-74.el7_6.7, bind-utils 9.9.4-74.el7_6.7, bind-license 9.9.4-74.el7_6.7, bind-libs-lite 9.9.4-74.el7_6.7
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1478
  • Red Hat Enterprise Linux ComputeNode EUS (v. 7.7) bind 9.11.4-9.P2.el7_7.5, bind-libs 9.11.4-9.P2.el7_7.5, bind-utils 9.11.4-9.P2.el7_7.5, bind-license 9.11.4-9.P2.el7_7.5, bind-libs-lite 9.11.4-9.P2.el7_7.5, bind-export-libs 9.11.4-9.P2.el7_7.5
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1477
  • Red Hat Enterprise Linux ComputeNode Optional (v. 7) bind 9.11.4-26.P2.el7_9.5, bind-sdb 9.11.4-26.P2.el7_9.5, bind-chroot 9.11.4-26.P2.el7_9.5, bind-pkcs11 9.11.4-26.P2.el7_9.5, bind-sdb-chroot 9.11.4-26.P2.el7_9.5, bind-pkcs11-libs 9.11.4-26.P2.el7_9.5, +1 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1469
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.6) bind 9.9.4-74.el7_6.7, bind-sdb 9.9.4-74.el7_6.7, bind-chroot 9.9.4-74.el7_6.7, bind-pkcs11 9.9.4-74.el7_6.7, bind-sdb-chroot 9.9.4-74.el7_6.7, bind-pkcs11-libs 9.9.4-74.el7_6.7, +1 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1478
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.7) bind 9.11.4-9.P2.el7_7.5, bind-sdb 9.11.4-9.P2.el7_7.5, bind-chroot 9.11.4-9.P2.el7_7.5, bind-pkcs11 9.11.4-9.P2.el7_7.5, bind-sdb-chroot 9.11.4-9.P2.el7_7.5, bind-pkcs11-libs 9.11.4-9.P2.el7_7.5, +1 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1477
  • Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) bind 9.9.4-74.el7_6.7, bind-libs 9.9.4-74.el7_6.7, bind-utils 9.9.4-74.el7_6.7, bind-chroot 9.9.4-74.el7_6.7, bind-pkcs11 9.9.4-74.el7_6.7, bind-license 9.9.4-74.el7_6.7, +3 more Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) bind-sdb 9.9.4-74.el7_6.7, bind-pkcs11 9.9.4-74.el7_6.7, bind-sdb-chroot 9.9.4-74.el7_6.7, bind-pkcs11-libs 9.9.4-74.el7_6.7, bind-pkcs11-utils 9.9.4-74.el7_6.7
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1478
  • Red Hat Enterprise Linux Server (v. 6 ELS) bind 9.8.2-0.68.rc1.el6_10.11, bind-libs 9.8.2-0.68.rc1.el6_10.11, bind-utils 9.8.2-0.68.rc1.el6_10.11, bind-chroot 9.8.2-0.68.rc1.el6_10.11
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1468
  • Red Hat Enterprise Linux Server (v. 7) bind 9.11.4-26.P2.el7_9.5, bind-libs 9.11.4-26.P2.el7_9.5, bind-utils 9.11.4-26.P2.el7_9.5, bind-chroot 9.11.4-26.P2.el7_9.5, bind-pkcs11 9.11.4-26.P2.el7_9.5, bind-license 9.11.4-26.P2.el7_9.5, +4 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1469
  • Red Hat Enterprise Linux Server AUS (v. 7.2) bind 9.9.4-29.el7_2.11, bind-libs 9.9.4-29.el7_2.11, bind-utils 9.9.4-29.el7_2.11, bind-chroot 9.9.4-29.el7_2.11, bind-pkcs11 9.9.4-29.el7_2.11, bind-license 9.9.4-29.el7_2.11, +3 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1476
  • Red Hat Enterprise Linux Server AUS (v. 7.3) bind 9.9.4-50.el7_3.6, bind-libs 9.9.4-50.el7_3.6, bind-utils 9.9.4-50.el7_3.6, bind-chroot 9.9.4-50.el7_3.6, bind-pkcs11 9.9.4-50.el7_3.6, bind-license 9.9.4-50.el7_3.6, +3 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1475
  • Red Hat Enterprise Linux Server AUS (v. 7.4) bind 9.9.4-51.el7_4.6, bind-libs 9.9.4-51.el7_4.6, bind-utils 9.9.4-51.el7_4.6, bind-chroot 9.9.4-51.el7_4.6, bind-pkcs11 9.9.4-51.el7_4.6, bind-license 9.9.4-51.el7_4.6, +3 more Red Hat Enterprise Linux Server E4S (v. 7.4) bind 9.9.4-51.el7_4.6, bind-libs 9.9.4-51.el7_4.6, bind-utils 9.9.4-51.el7_4.6, bind-chroot 9.9.4-51.el7_4.6, bind-pkcs11 9.9.4-51.el7_4.6, bind-license 9.9.4-51.el7_4.6, +3 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1479
  • Red Hat Enterprise Linux Server EUS (v. 7.6) bind 9.9.4-74.el7_6.7, bind-libs 9.9.4-74.el7_6.7, bind-utils 9.9.4-74.el7_6.7, bind-chroot 9.9.4-74.el7_6.7, bind-pkcs11 9.9.4-74.el7_6.7, bind-license 9.9.4-74.el7_6.7, +3 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1478
  • Red Hat Enterprise Linux Server EUS (v. 7.7) bind 9.11.4-9.P2.el7_7.5, bind-libs 9.11.4-9.P2.el7_7.5, bind-utils 9.11.4-9.P2.el7_7.5, bind-chroot 9.11.4-9.P2.el7_7.5, bind-pkcs11 9.11.4-9.P2.el7_7.5, bind-license 9.11.4-9.P2.el7_7.5, +4 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1477
  • Red Hat Enterprise Linux Server Optional (v. 6 ELS) bind-sdb 9.8.2-0.68.rc1.el6_10.11
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1468
  • Red Hat Enterprise Linux Server Optional (v. 7) bind-sdb 9.11.4-26.P2.el7_9.5, bind-sdb-chroot 9.11.4-26.P2.el7_9.5
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1469
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.2) bind-sdb 9.9.4-29.el7_2.11, bind-sdb-chroot 9.9.4-29.el7_2.11
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1476
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.3) bind-sdb 9.9.4-50.el7_3.6, bind-sdb-chroot 9.9.4-50.el7_3.6
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1475
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.4) bind-sdb 9.9.4-51.el7_4.6, bind-sdb-chroot 9.9.4-51.el7_4.6 Red Hat Enterprise Linux Server Optional E4S (v. 7.4) bind-sdb 9.9.4-51.el7_4.6, bind-sdb-chroot 9.9.4-51.el7_4.6
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1479
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.6) bind-sdb 9.9.4-74.el7_6.7, bind-pkcs11 9.9.4-74.el7_6.7, bind-sdb-chroot 9.9.4-74.el7_6.7, bind-pkcs11-libs 9.9.4-74.el7_6.7, bind-pkcs11-utils 9.9.4-74.el7_6.7
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1478
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.7) bind-sdb 9.11.4-9.P2.el7_7.5, bind-sdb-chroot 9.11.4-9.P2.el7_7.5
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1477
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.4) bind-sdb 9.9.4-51.el7_4.6, bind-sdb-chroot 9.9.4-51.el7_4.6 Red Hat Enterprise Linux Server TUS (v. 7.4) bind 9.9.4-51.el7_4.6, bind-libs 9.9.4-51.el7_4.6, bind-utils 9.9.4-51.el7_4.6, bind-chroot 9.9.4-51.el7_4.6, bind-pkcs11 9.9.4-51.el7_4.6, bind-license 9.9.4-51.el7_4.6, +3 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1479
  • Red Hat Enterprise Linux Workstation (v. 7) bind 9.11.4-26.P2.el7_9.5, bind-libs 9.11.4-26.P2.el7_9.5, bind-utils 9.11.4-26.P2.el7_9.5, bind-chroot 9.11.4-26.P2.el7_9.5, bind-pkcs11 9.11.4-26.P2.el7_9.5, bind-license 9.11.4-26.P2.el7_9.5, +4 more Red Hat Enterprise Linux Workstation Optional (v. 7) bind-sdb 9.11.4-26.P2.el7_9.5, bind-sdb-chroot 9.11.4-26.P2.el7_9.5
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2021:1469
  • 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

11.70% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • ISC BIND9

Classification

Weakness

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.