CVE-2020-24659

What it is

An issue was discovered in GnuTLS before 3.6.15. A server can trigger a NULL pointer dereference in a TLS 1.3 client if a no_renegotiation alert is sent with unexpected timing, and then an invalid second handshake occurs. The crash happens in the application's error handling path, where the gnutls_deinit function is called after detecting a handshake failure.

At a glance

Exploitability

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

Exploit odds

3.8% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2020-09-04 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-14 10:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.8% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-09-04 15:15 UTC

Last modified

2026-10-14 10:17 UTC

Exploit probability

3.8% · EPSS, next 30 days

Weakness

CWE-476 · NULL pointer dereference

Record status

Modified

Affected

• Gnu Gnutls < 3.6.15
• Fedoraproject Fedora 32
• Fedoraproject Fedora 33
• Opensuse Leap 15.1
• Opensuse Leap 15.2
• Canonical Ubuntu Linux 20.04

Attack profile CVSS 3.1 · 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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