CVE-2017-5495

All versions of Quagga, 0.93 through 1.1.0, are vulnerable to an unbounded memory allocation in the telnet 'vty' CLI, leading to a Denial-of-Service of Quagga daemons, or even the entire host. When Quagga daemons are configured with their telnet CLI enabled, anyone who can connect to the TCP ports can trigger this vulnerability, prior to authentication. Most distributions restrict the Quagga telnet interface to local access only by default. The Quagga telnet interface 'vty' input buffer grows automatically, without bound, so long as a newline is not entered. This allows an attacker to cause the Quagga daemon to allocate unbounded memory by sending very long strings without a newline. Eventually the daemon is terminated by the system, or the system itself runs out of memory. This is fixed in Quagga 1.1.1 and Free Range Routing (FRR) Protocol Suite 2017-01-10.

Published: 2017-01-24 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-5495 is rated High Risk (68.9/100): CVSS High severity, with high exploitation likelihood (EPSS 18.80%, 97th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +15.04% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-5495

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 3.76% 18.80% +15.04%
2 2026-05-29 6.87% 3.76% -3.12%
3 2026-05-26 — 6.87% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-5495

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
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]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C 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:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2017-5495

OS Trackers for CVE-2017-5495

vendor priority summary link
alpine — CVE-2017-5495: 1 source package rows (quagga); 10 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 0. https://security.alpinelinux.org/vuln/CVE-2017-5495
redhat medium — https://access.redhat.com/security/cve/CVE-2017-5495
suse medium CVE-2017-5495 severity moderate: SUSE including 37 source package names (libfpm_pb0, libfpm_pb0-1.1.1-17.3.3, …), 170 product×package rows across 43 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (43 product lines)): Fixed 108, Known Not Affected 62. https://www.suse.com/security/cve/CVE-2017-5495/
ubuntu low CVE-2017-5495 low priority: Ubuntu including 1 source packages (quagga), 7 status rows across 7 suites (artful, precise, trusty, upstream, xenial, yakkety, zesty): released 3, ignored 2, not-affected 2. https://ubuntu.com/security/CVE-2017-5495

Affected software / configurations for CVE-2017-5495

Vendor Product Version Raw CPE
quagga quagga <= 1.1.0 cpe:2.3:a:quagga:quagga:*:*:*:*:*:*:*:*

References for CVE-2017-5495

cvelogic Threat Intelligence