CVE-2017-9109

CVE-2017-9109 is a critical-severity vulnerability in Gnu Adns with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

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.

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 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-9109 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-9109?
CVE-2017-9109 primarily affects Gnu Adns. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-9109?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-9109 published?
CVE-2017-9109 was published on 2020-06-18 and last updated on 2026-06-17.

References

Affected products (4)

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