vulntracker.iovulntracker.io
© 2026 vulntracker.io

CVE-2021-25219

Lame cache can be abused to severely degrade resolver performance

MEDIUM
5.3
CVSS Score
Published: October 27, 2021 at 09:10 PM UTC
Updated: June 17, 2026 at 03:41 AM UTC
23 products affected across 6 vendorsDebian LinuxFedoraCloud Backup

Using BIND9 by ISC?

Get instant alerts when new vulnerabilities affect BIND9 - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Start FreeSign In
Severity
MEDIUM5.3
Exploit prediction
EPSS 11%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Debian Linux· Debiandrupal
95%
10.011.09.0
Fedora· Fedora Projectrpm
95%
333435
BIND· Isc
95%
v < 9.11.36v < 9.11.36-S1v < 9.16.22v < 9.16.22-S1v < 9.17.199.12.0 ≤ v < 9.16.229.17.0 ≤ v < 9.17.199.3.0 ≤ v < 9.11.369.10.5 s19.10.7 s19.11.12 s19.11.21 s19.11.27 s19.11.29 s19.11.3 s19.11.35 s19.11.5 s39.11.5 s59.11.5 s69.11.6 s19.11.7 s19.11.8 s19.16.11 s19.16.13 s19.16.21 s19.16.8 s19.9.12 s19.9.13 s19.9.3 s1
Affected range stops below 9.11.36, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.11.36-S1, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.16.22, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.16.22-S1, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.17.19, so it looks safe — our inference, not a vendor statement
Cloud Backup· NetAppdrupal
95%
All versions
H300E Firmware· NetAppdrupal
95%
All versions
netapp-h300e (same device)
H300S Firmware· NetAppdrupal
95%
All versions
netapp-h300s (same device)
H410C Firmware· NetAppdrupal
95%
All versions
netapp-h410c (same device)
H410S Firmware· NetAppdrupal
95%
All versions
netapp-h410s (same device)
H500E Firmware· NetAppdrupal
95%
All versions
netapp-h500e (same device)
H500S Firmware· NetAppdrupal
95%
All versions
netapp-h500s (same device)

References (10)

x_refsource_CONFIRMPatchThird Party Advisory
Source: [email protected]
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
Vendor Advisory
Source: [email protected]
https://kb.isc.org/v1/docs/cve-2021-25219
Mailing ListThird Party Advisory
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2021/11/msg00001.html
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EF4NAVRV4H3W4GA3LGGZYUKD3HSJBAVW/
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YGV7SA27CTYLGFJSPUM3V36ZWK7WWDI4/
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YTKC4E3HUOLYN5IA4EBL4VAQSWG2ZVTX/
Vendor AdvisoryThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202210-25
Third Party Advisory
Source: [email protected]
https://security.netapp.com/advisory/ntap-20211118-0002/

CVSS

5.3MEDIUMisc
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create accountSign in
Free plan, no card