CVE-2021-25219

Lame cache can be abused to severely degrade resolver performance

At a glance

Severity: MEDIUM 5.3
EPSS: EPSS 10.95 % · percentile 96 (2026-10-27)
State: PUBLISHED
Published: 2021-10-27
Updated: 2024-09-16
Assigner: isc
NVD status: Modified

Description

In BIND 9.3.0 -> 9.11.35, 9.12.0 -> 9.16.21, and versions 9.9.3-S1 -> 9.11.35-S1 and 9.16.8-S1 -> 9.16.21-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.18 of the BIND 9.17 development branch, exploitation of broken authoritative servers using a flaw in response processing can cause degradation in BIND resolver performance. The way the lame cache is currently designed makes it possible for its internal data structures to grow almost infinitely, which may cause significant delays in client query processing.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	MEDIUM 5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	isc
CVSS 3.1	MEDIUM 5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	NVD · security-officer@isc.org (Secondary)
CVSS 3.1	MEDIUM 5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	NVD · nvd@nist.gov (Primary)
CVSS 2.0	MEDIUM 5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P	NVD · nvd@nist.gov (Primary)

European references

ENISA EUVD · EUVD-2021-12130
GCVE · GCVE-0-2021-25219

CERT-FR advisories

CERTFR-2025-AVI-0756 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
CERTFR-2022-AVI-216 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
CERTFR-2021-AVI-838 — Vulnérabilité dans les produits Synology · cert.ssi.gouv.fr
CERTFR-2021-AVI-828 — Vulnérabilité dans ISC BIND · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:* ≥ 9.3.0 < 9.11.36
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:* ≥ 9.12.0 < 9.16.22
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:* ≥ 9.17.0 < 9.17.19
cpe:2.3:a:isc:bind:9.9.3:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.9.12:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.9.13:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.10.5:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.10.7:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.3:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.5:s3:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.5:s5:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.5:s6:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.6:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.7:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.8:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.12:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.21:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.27:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.29:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.11.35:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.16.8:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.16.11:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.16.13:s1:*:*:supported_preview:*:*:*
cpe:2.3:a:isc:bind:9.16.21:s1:*:*:supported_preview:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h300e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h500e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h700e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h410c_firmware:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
cpe:2.3:a:siemens:sinec_infrastructure_network_services:*:*:*:*:*:*:*:* < 1.0.1.1
+3 more

Affected products

Product	Versions
ISC · BIND9	affected Open Source Branches 9.3 through 9.11 9.3.0 through versions before 9.11.36 ; affected Open Source Branches 9.12 through 9.16 9.12.0 through versions before 9.16.22 ; affected Supported Preview Branches 9.9-S through 9.11-S 9.9.3-S1 through versions before 9.11.36-S1 ; affected Supported Preview Branch 9.16-S 9.16.8-S1 through versions before 9.16.22-S1 ; affected Development Branch 9.17 9.17.0 through versions before 9.17.19

Product

Versions

ISC · BIND9

affected Open Source Branches 9.3 through 9.11 9.3.0 through versions before 9.11.36 ; affected Open Source Branches 9.12 through 9.16 9.12.0 through versions before 9.16.22 ; affected Supported Preview Branches 9.9-S through 9.11-S 9.9.3-S1 through versions before 9.11.36-S1 ; affected Supported Preview Branch 9.16-S 9.16.8-S1 through versions before 9.16.22-S1 ; affected Development Branch 9.17 9.17.0 through versions before 9.17.19

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD