CVE-2018-5381 [Medium] | Denial of Service in Quagga

CVE-2018-5381 is rated Moderate Risk (58.8/100): CVSS Medium severity, with high exploitation likelihood (EPSS 5.59%, 90th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +1.24% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-27	4.35%	5.59%	+1.24%
2	2025-12-18	4.04%	4.35%	+0.31%
3	2025-11-21	—	4.04%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-27

4.35%

5.59%

+1.24%

2025-12-18

4.04%

4.35%

+0.31%

2025-11-21

—

4.04%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.0	MEDIUM	`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:L) A normal user session is enough; they don’t have to be admin. 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:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	3.6	[email protected]
7.5	3.0	HIGH	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:N/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:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	10.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.0

MEDIUM

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:L): A normal user session is enough; they don’t have to be admin.
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:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

3.6

[email protected]

7.5

3.0

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

3.6

[email protected]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:N/I:N/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:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

2.9

[email protected]

OS Trackers for CVE-2018-5381

vendor	priority	summary	link
`alpine`	high	CVE-2018-5381: 1 source package rows (quagga); 5 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 5.	https://security.alpinelinux.org/vuln/CVE-2018-5381
`gentoo`	high	CVE-2018-5381: 1 GLSA(s) (201804-17), 1 atom(s) (net-misc/quagga); latest impact high.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-5381
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2018-5381
`ubuntu`	medium	CVE-2018-5381 medium priority: Ubuntu including 1 source packages (quagga), 4 status rows across 4 suites (artful, trusty, upstream, xenial): released 4.	https://ubuntu.com/security/CVE-2018-5381

Affected software / configurations for CVE-2018-5381

Vendor	Product	Version	Raw CPE
quagga	quagga	<= 1.2.2	cpe:2.3:a:quagga:quagga::::::::
canonical	ubuntu_linux	14.04	cpe:2.3:o:canonical:ubuntu_linux:14.04::::lts:::
canonical	ubuntu_linux	16.04	cpe:2.3:o:canonical:ubuntu_linux:16.04::::lts:::
canonical	ubuntu_linux	17.10	cpe:2.3:o:canonical:ubuntu_linux:17.10:::::::*
debian	debian_linux	7.0	cpe:2.3:o:debian:debian_linux:7.0:::::::*
debian	debian_linux	8.0	cpe:2.3:o:debian:debian_linux:8.0:::::::*
debian	debian_linux	9.0	cpe:2.3:o:debian:debian_linux:9.0:::::::*
siemens	ruggedcom_rox_ii_firmware	< 2.13.0	cpe:2.3:o:siemens:ruggedcom_rox_ii_firmware::::::::

References for CVE-2018-5381

URL	Tags
http://savannah.nongnu.org/forum/forum.php?forum_id=9095	Third Party Advisory
http://www.kb.cert.org/vuls/id/940439	Third Party Advisory US Government Resource
https://cert-portal.siemens.com/productcert/pdf/ssa-451142.pdf	Mitigation Third Party Advisory
https://gogs.quagga.net/Quagga/quagga/src/master/doc/security/Quagga-2018-1975.txt	Vendor Advisory
https://lists.debian.org/debian-lts-announce/2018/02/msg00021.html	Mailing List Third Party Advisory
https://security.gentoo.org/glsa/201804-17	Third Party Advisory
https://usn.ubuntu.com/3573-1/	Third Party Advisory
https://www.debian.org/security/2018/dsa-4115	Third Party Advisory

URL

CVE-2018-5381

Exploit prediction scoring system (EPSS) score for CVE-2018-5381

Common vulnerability scoring system (CVSS) metrics for CVE-2018-5381

Weakness enumeration for CVE-2018-5381

OS Trackers for CVE-2018-5381

Affected software / configurations for CVE-2018-5381

References for CVE-2018-5381