CVE-2017-9109 [Critical] | Memory Corruption in Adns

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-22	0.67%	0.89%	+0.22%
2	2025-11-21	0.89%	0.67%	-0.22%
3	2025-11-18	—	0.89%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-22

0.67%

0.89%

+0.22%

2025-11-21

0.89%

0.67%

-0.22%

2025-11-18

—

0.89%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/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:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/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:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

OS Trackers for CVE-2017-9109

vendor	priority	summary	link
`debian`	unimportant	CVE-2017-9109 unimportant priority: Debian including 1 source packages (adns), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2017-9109
`suse`	high	CVE-2017-9109 severity important: SUSE including 18 source package names (24.164:libadns1-1.4-103.3.1, 26.196:libadns1-1.4-103.3.1, …), 60 product×package rows across 52 product lines (Container caasp/v4/nginx-ingress-controller, Container suse/ltss/sle12.5/sles12sp5, … (52 product lines)): Fixed 60.	https://www.suse.com/security/cve/CVE-2017-9109/
`ubuntu`	medium	CVE-2017-9109 medium priority: Ubuntu including 1 source packages (adns), 17 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 11, needed 3, DNE 1, ignored 1, needs-triage 1.	https://ubuntu.com/security/CVE-2017-9109

Affected software / configurations for CVE-2017-9109

Vendor	Product	Version	Raw CPE
gnu	adns	< 1.5.2	cpe:2.3:a:gnu:adns::::::::
opensuse	leap	15.1	cpe:2.3:o:opensuse:leap:15.1:::::::*
fedoraproject	fedora	31	cpe:2.3:o:fedoraproject:fedora:31:::::::*
fedoraproject	fedora	32	cpe:2.3:o:fedoraproject:fedora:32:::::::*

References for CVE-2017-9109

URL	Tags
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00037.html	Mailing List Third Party Advisory
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git	Third Party Advisory
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git%3Ba=blob%3Bf=changelog
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TRVHN3GGVNQWAOL3PWC5FLAV7HUESLZR/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UGFZ4SPV6KFQK6ZNUZFB5Y32OYFOM5YJ/
https://www.chiark.greenend.org.uk/pipermail/adns-announce/2020/000004.html	Release Notes Third Party Advisory

URL

CVE-2017-9109

Exploit prediction scoring system (EPSS) score for CVE-2017-9109

Common vulnerability scoring system (CVSS) metrics for CVE-2017-9109

Weakness enumeration for CVE-2017-9109

OS Trackers for CVE-2017-9109

Affected software / configurations for CVE-2017-9109

References for CVE-2017-9109