CVE-2020-24659: canonical ubuntu_linux NULL Pointer Dereference
Vulnerability summary
CVE-2020-24659 is a high (CVSS 7.5) NULL Pointer Dereference vulnerability in canonical ubuntu_linux. EPSS estimates a 3.83% chance of exploitation in the next 30 days, higher than 89.9% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 0 · Related 2Timeline
- 04-09-2020PublishedVulnerability first disclosed.
- 14-10-2026Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
8 scores · 7 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · Red hatEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · WolfiEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · ChainguardEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
3.83%
Chance of exploitation in the next 30 days
Percentile
90%
Versus all other CVEs
30-day change
+0.10 pp
From 3.73% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (gitlab.com)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Redhat10 products
- gnutls< 0:3.6.14-7.el8_3
- gnutls-c++< 0:3.6.14-7.el8_3
- gnutls-c++-debuginfo< 0:3.6.14-7.el8_3
- gnutls-dane< 0:3.6.14-7.el8_3
- gnutls-dane-debuginfo< 0:3.6.14-7.el8_3
Suse7 products
- gnutls&distro=SUSE Linux Enterprise High Performance Computing 15-ESPOS< 3.6.7-6.34.1
- gnutls&distro=SUSE Linux Enterprise High Performance Computing 15-LTSS< 3.6.7-6.34.1
- gnutls&distro=SUSE Linux Enterprise Module for Basesystem 15 SP1< 3.6.7-6.34.1
- gnutls&distro=SUSE Linux Enterprise Module for Basesystem 15 SP2< 3.6.7-14.4.1
- gnutls&distro=SUSE Linux Enterprise Module for Certifications 15 SP3< 3.6.7-14.4.1
Opensuse3 products
- leapEOL15.1 | 15.2
- gnutls&distro=openSUSE Leap 15.1< 3.6.7-lp151.2.21.1
- gnutls&distro=openSUSE Leap 15.2< 3.6.7-lp152.9.3.2
Alpine1 product
- gnutls< 3.6.15-r0
Canonical1 product
- ubuntu_linuxEOL20.04
Chainguard1 product
- gnutlsAll versions (No fix recorded)
Debian1 product
- gnutls28< 3.6.15-1
Fedoraproject1 product
- fedoraEOL32 | 33
Gnu1 product
- gnutls< 3.6.15
Mageia1 product
- gnutls< 3.6.15-1.mga7
Ubuntu1 product
- gnutls28< 3.6.13-2ubuntu1.3
Wolfi1 product
- gnutlsAll versions (No fix recorded)
12 vendors · 29 products
References
33 links- gitlab.com/gnutls/gnutls/-/issues/1071X Refsource MISCREPORTExploitIssue TrackingThird Party Advisory
- security.gentoo.org/glsa/202009-01Vendor AdvisoryX Refsource GENTOOREPORTAdvisoryThird Party Advisory
- lists.opensuse.org/opensuse-security-announce/2020-10/msg00054.htmlVendor AdvisoryX Refsource SUSEAdvisoryMailing ListThird Party Advisory
- lists.opensuse.org/opensuse-security-announce/2020-10/msg00060.htmlVendor AdvisoryX Refsource SUSEAdvisoryMailing ListThird Party Advisory
Show all 33 references
- lists.opensuse.org/archives/…Advisory
- lists.opensuse.org/archives/…Advisory