CVE-2019-6476
An error in QNAME minimization code can cause BIND to exit with an assertion failure
- 5.9MediumCVSS base score
- 3.0%Exploitation in 30 daysEPSS · top 13% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By isc
- 9 months later
· 9 months later
Published
- 5 years later
· 5 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| iscCNA (assigner) | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 3.0% · top 13% of all CVEs (10 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.
Affected products
What to do
Solution: Upgrade to the patched release most closely related to your current version of BIND: + BIND 9.14.7 + BIND 9.15.5
Workaround: ervers which have QNAME minimization turned on are potentially vulnerable to this defect if they are running an affected version of BIND. The vulnerability can be avoided by disabling QNAME minimization using "qname-minimization disabled;" in the global options section of named.conf (Note: the default value for the qname-minimization setting in the 9.14 and 9.15 branches is "relaxed". To make use of this workaround it must be explicitly disabled.)
References
3
- https://kb.isc.org/docs/cve-2019-6476 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://security.netapp.com/advisory/ntap-20191024-0004/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://support.f5.com/csp/article/K42238532?utm_source=f5support&%3Butm_medium=RSS (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2019-16036 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2019-6476)Record last updated .