CVE-2020-24659

Exp

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.

Published: 2020-09-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-24659 is rated High Exploit Risk (76/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.73%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2020-24659

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-24659

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 3.63% 3.73% +0.10%
2 2026-02-28 3.40% 3.63% +0.24%
3 2025-12-28 — 3.40% —

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-24659

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/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]

Weakness enumeration for CVE-2020-24659

OS Trackers for CVE-2020-24659

vendor priority summary link
alpine high CVE-2020-24659: 1 source package rows (gnutls); 30 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 20. https://security.alpinelinux.org/vuln/CVE-2020-24659
debian not yet assigned CVE-2020-24659 not yet assigned priority: Debian including 1 source packages (gnutls28), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-24659
gentoo low CVE-2020-24659: 1 GLSA(s) (202009-01), 1 atom(s) (net-libs/gnutls); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-24659
redhat medium — https://access.redhat.com/security/cve/CVE-2020-24659
suse medium CVE-2020-24659 severity moderate: SUSE including 398 source package names (0.1.0:libgnutls30-3.6.7-6.34.1, 0.1.75:libgnutls30-3.6.7-6.34.1, …), 556 product×package rows across 140 product lines (Container caasp/v4/389-ds, Container caasp/v4/busybox, … (140 product lines)): Fixed 347, Known Affected 157, Known Not Affected 52. https://www.suse.com/security/cve/CVE-2020-24659/
ubuntu medium CVE-2020-24659 medium priority: Ubuntu including 1 source packages (gnutls28), 5 status rows across 5 suites (bionic, focal, trusty, upstream, xenial): not-affected 2, released 2, DNE 1. https://ubuntu.com/security/CVE-2020-24659

Affected software / configurations for CVE-2020-24659

Vendor Product Version Raw CPE
gnu gnutls < 3.6.15 cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*

References for CVE-2020-24659

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00054.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00060.html Mailing List Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/issues/1071 Exploit Issue Tracking Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/62BUAI4FQQLG6VTKRT7SUZPGJJ4NASQ3/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AWN56FDLQQXT2D2YHNI4TYH432TDMQ7N/
https://security.gentoo.org/glsa/202009-01 Third Party Advisory
https://security.netapp.com/advisory/ntap-20200911-0006/ Third Party Advisory
https://usn.ubuntu.com/4491-1/ Third Party Advisory
https://www.gnutls.org/security-new.html#GNUTLS-SA-2020-09-04 Vendor Advisory
cvelogic Threat Intelligence