CVE-2017-9109: An issue was discovered in adns before 1.5.2. It fails to ignore apparent answers before the first RR that was found the first time. when this is fixe...

Description

An issue was discovered in adns before 1.5.2. It fails to ignore apparent answers before the first RR that was found the first time. when this is fixed, the second answer scan finds the same RRs at the first. Otherwise, adns can be confused by interleaving answers for the CNAME target, with the CNAME itself. In that case the answer data structure (on the heap) can be overrun. With this fixed, it prefers to look only at the answer RRs which come after the CNAME, which is at least arguably correct.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.05%

78.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
Gnu	Adns	< 1.5.2
Opensuse	Leap	15.1
Fedoraproject	Fedora	31
Fedoraproject	Fedora	32

References

Timeline

Published: Jun 18, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-9109?

An issue was discovered in adns before 1.5.2. It fails to ignore apparent answers before the first RR that was found the first time. when this is fixed, the second answer scan finds the same RRs at the first. Otherwise, adns can be confused by interleaving answers for the CNAME target, with the CNAME itself. In that case the answer data structure (on the heap) can be overrun. With this fixed, it prefers to look only at the answer RRs which come after the CNAME, which is at least arguably correct.

How severe is CVE-2017-9109?

CVE-2017-9109 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.05% probability of exploitation in the next 30 days.

How do I fix CVE-2017-9109?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.