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NVD / CVE Program· CNA mitre

CVE-2020-24659: An issue was discovered in GnuTLS before 3.6.15.

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 3.8% (FIRST EPSS); higher than 90.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: gnutls (Alpine:v3.10) 3.6.15-r0; gnutls28 (Debian:12) 3.6.15-1; gnutls (openSUSE:Leap 15.1) 3.6.7-lp151.2.21.1.

Low priority for now. Upgrade to gnutls (Alpine:v3.10) 3.6.15-r0; gnutls28 (Debian:12) 3.6.15-1; gnutls (openSUSE:Leap 15.1) 3.6.7-lp151.2.21.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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
Sep 4, 2020
Updated
Oct 14, 2026
EPSS
3.8% · 90th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.8%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
gnugnutls
fedoraprojectfedora
opensuseleap
canonicalubuntu linux

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The GnuTLS version can't be seen from outside; the free SSL checker tests your certificate, enabled TLS versions and weak ciphers. Confirm the version on your server with the package manager.

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • canonical ubuntu linux20.04
  • fedoraproject fedora32
  • fedoraproject fedora33
  • gnu gnutlsbefore 3.6.15
  • opensuse leap15.1
  • opensuse leap15.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.10gnutlsbefore 3.6.15-r03.6.15-r0
Debian:12gnutls28before 3.6.15-13.6.15-1
openSUSE:Leap 15.1gnutlsbefore 3.6.7-lp151.2.21.13.6.7-lp151.2.21.1
openSUSE:Leap 15.2gnutlsbefore 3.6.7-lp152.9.3.23.6.7-lp152.9.3.2
Red Hat:enterprise_linux:8::appstreamgnutls-c++before 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-c++-debuginfobefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-danebefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-dane-debuginfobefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-debuginfobefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-debugsourcebefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-develbefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-utilsbefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::appstreamgnutls-utils-debuginfobefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
Red Hat:enterprise_linux:8::baseosgnutlsbefore 0:3.6.14-7.el8_30:3.6.14-7.el8_3
SUSE:Linux Enterprise Module for Basesystem 15 SP1gnutlsbefore 3.6.7-6.34.13.6.7-6.34.1
SUSE:Linux Enterprise Module for Basesystem 15 SP2gnutlsbefore 3.6.7-14.4.13.6.7-14.4.1

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-5334Double free vulnerability in the gnutls_x509_ext_import_proxy function in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allows remote…
    49Plan
  • CVE-2019-3829A vulnerability was found in gnutls versions from 3.5.8 before 3.6.7.
    48Plan
  • CVE-2008-1948The _gnutls_server_name_recv_params function in lib/ext_server_name.c in libgnutls in gnutls-serv in GnuTLS before 2.2.4 does not properly…
    44Plan

Published before and after this one in the same product

  • ← EarlierCVE-2020-11501Apr 3, 2020 · GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS.
    30Monitor
  • ← EarlierCVE-2020-13777Jun 4, 2020 · GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an…
    36Monitor
  • Later →CVE-2021-20231Mar 12, 2021 · A flaw was found in gnutls.
    40Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:gnutls3.6.15-r0 · Alpine:v3.10Package registry (OSV)
debian:gnutls283.6.15-1 · Debian:12Package registry (OSV)
opensuse:gnutls3.6.7-lp151.2.21.1 · openSUSE:Leap 15.1Package registry (OSV)
red hat:gnutls0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:gnutls-c++0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-c++-debuginfo0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-dane0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-dane-debuginfo0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-debuginfo0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-debugsource0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-devel0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-utils0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:gnutls-utils-debuginfo0:3.6.14-7.el8_3 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
suse:gnutls3.6.7-14.4.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records