CVE-2019-6476 | An error in QNAME minimization code can cause BIND to exit with an assertion failure

A defect in code added to support QNAME minimization can cause named to exit with an assertion failure if a forwarder returns a referral rather than resolving the query. This affects BIND versions 9.14.0 up to 9.14.6, and 9.15.0 up to 9.15.4.

Published: 2019-10-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-6476 is rated Moderate Risk (52.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.88%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-6476

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 3.58% 2.88% -0.70%
2 2026-06-15 1.27% 3.58% +2.31%
3 2025-12-18 — 1.27% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-6476

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2019-6476

OS Trackers for CVE-2019-6476

vendor priority summary link
alpine high CVE-2019-6476: 1 source package rows (bind); 20 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 10. https://security.alpinelinux.org/vuln/CVE-2019-6476
debian unimportant CVE-2019-6476 unimportant priority: Debian including 1 source packages (bind9), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-6476
redhat medium — https://access.redhat.com/security/cve/CVE-2019-6476
suse medium CVE-2019-6476 severity moderate: SUSE including 319 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 670 product×package rows across 59 product lines (SUSE CaaS Platform 3.0, SUSE CaaS Platform 4.0, … (59 product lines)): Known Not Affected 370, Known Affected 157, Fixed 143. https://www.suse.com/security/cve/CVE-2019-6476/
ubuntu medium CVE-2019-6476 medium priority: Ubuntu including 1 source packages (bind9), 5 status rows across 5 suites (bionic, disco, trusty, upstream, xenial): not-affected 4, needs-triage 1. https://ubuntu.com/security/CVE-2019-6476

Affected software / configurations for CVE-2019-6476

Vendor Product Version Raw CPE
isc bind >= 9.14.0, <= 9.14.6 cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
isc bind >= 9.15.0, <= 9.15.4 cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*

References for CVE-2019-6476

cvelogic Threat Intelligence