CVE-2017-9109Network attack vector

Memory corruption via interleaved CNAME answers

Published Jun 18, 2020 · Updated Aug 5, 2024

Heap-based buffer overflow in GNU adns before 1.5.2 allows remote attackers to corrupt memory via crafted DNS responses. The answer parser fails to exclude records preceding the first matched record during its second scan, so interleaving CNAME and target records overruns a heap answer structure. The attacker must control or spoof a DNS response containing the interleaved records; the published record specifies no resulting behavior beyond the heap overrun.

CVSS severity9.8
Critical
EPSS probability2.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in GNU adns before 1.5.2 allows remote attackers to corrupt memory via crafted DNS responses. The answer parser fails to exclude records preceding the first matched record during its second scan, so interleaving CNAME and target records overruns a heap answer structure. The attacker must control or spoof a DNS response containing the interleaved records; the published record specifies no resulting behavior beyond the heap overrun.

The record

CVE
CVE-2017-9109
Published
Jun 18, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5SUSECVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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