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CVE-2020-8621

Attempting QNAME minimization after forwarding can lead to an assertion failure in resolver.c

HIGH
7.5
CVSS Score
Published: August 21, 2020 at 08:50 PM UTC
Updated: June 17, 2026 at 03:26 AM UTC
5 products affected across 5 vendorsUbuntu LinuxLeapBIND

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Severity
HIGH7.5
Exploit prediction
EPSS 3%

Description

In BIND 9.14.0 -> 9.16.5, 9.17.0 -> 9.17.3, If a server is configured with both QNAME minimization and 'forward first' then an attacker who can send queries to it may be able to trigger the condition that will cause the server to crash. Servers that 'forward only' are not affected.

Affected

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

Ubuntu Linux· Canonicalrubygems
95%
16.0418.0420.04
BIND· Isc
95%
v ≥ 9.14.09.14.0 ≤ v ≤ 9.16.59.17.0 ≤ v ≤ 9.17.39.14.0
Steelstore Cloud Integrated Storage· NetApp
95%
All versions
Leap· openSUSEdrupal
95%
15.115.2
DNS Server· Synology
95%
v < 2.2.2-5027
Affected range stops below 2.2.2-5027, so it looks safe — our inference, not a vendor statement

References (7)

Vendor Advisoryx_refsource_SUSEMailing ListThird Party Advisory
Source: [email protected]
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.html
Vendor Advisoryx_refsource_SUSEMailing ListThird Party Advisory
Source: [email protected]
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.html
x_refsource_CONFIRMVendor Advisory
Source: [email protected]
https://kb.isc.org/docs/cve-2020-8621
Vendor Advisoryx_refsource_GENTOOThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202008-19
x_refsource_CONFIRMThird Party Advisory
Source: [email protected]
https://security.netapp.com/advisory/ntap-20200827-0003/
Vendor Advisoryx_refsource_UBUNTUThird Party Advisory
Source: [email protected]
https://usn.ubuntu.com/4468-1/
x_refsource_CONFIRMThird Party Advisory
Source: [email protected]
https://www.synology.com/security/advisory/Synology_SA_20_19

CVSS

7.5HIGHisc
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-617

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