CVE-2017-5495

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

18.8% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2017-01-24 07:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 01:20 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 18.8% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2017-01-24 07:59 UTC

Last modified

2026-06-17 01:20 UTC

Exploit probability

18.8% · EPSS, next 30 days

Weakness

CWE-119 · Buffer errors

Record status

Modified

Affected

• Quagga ≤ 1.1.0

Attack profile CVSS 3.0 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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