Description
GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS. The earliest affected version is 3.6.3 (2018-07-16) because of an error in a 2017-10-06 commit. The DTLS client always uses 32 '\0' bytes instead of a random value, and thus contributes no randomness to a DTLS negotiation. This breaks the security guarantees of the DTLS protocol.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | gnutls28 | 3.6.13-2 | — |
| Debian 13 | gnutls28 | 3.6.13-2 | — |
| Debian 12 | gnutls28 | 3.6.13-2 | — |
| Debian 10 | gnutls28 | 3.6.7-4+deb10u3 | DSA-4652-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | gnutls +4 | 3.6.8-10.el8_2 | RHSA-2020:1998 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | gmp | 6.1.2-4.3.1 | SUSE-SU-2020:0948-2 |
| SLES 15 SP3 | libnettle | 3.4.1-4.12.1 | SUSE-SU-2020:0948-2 |
| SLES 15 SP1 | gmp | 6.1.2-4.3.1 | SUSE-SU-2020:0948-1 |
| SLES 15 SP1 | gnutls | 3.6.7-6.14.1 | SUSE-SU-2020:0948-1 |
| SLES 15 SP1 | libnettle | 3.4.1-4.12.1 | SUSE-SU-2020:0948-1 |
| SLES 15 | gmp | 6.1.2-4.3.1 | SUSE-SU-2020:0948-1 |
| SLES 15 | gnutls | 3.6.7-6.14.1 | SUSE-SU-2020:0948-1 |
| SLES 15 | libnettle | 3.4.1-4.12.1 | SUSE-SU-2020:0948-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 | gmp | 6.1.2-4.3.1 | SUSE-SU-2020:0948-1 |
| SLES for SAP 15 | gnutls | 3.6.7-6.14.1 | SUSE-SU-2020:0948-1 |
| SLES for SAP 15 | libnettle | 3.4.1-4.12.1 | SUSE-SU-2020:0948-1 |
| SLE HPC 15 | gmp | 6.1.2-4.3.1 | SUSE-SU-2020:0948-1 |
| SLE HPC 15 | gnutls | 3.6.7-6.14.1 | SUSE-SU-2020:0948-1 |
| SLE HPC 15 | libnettle | 3.4.1-4.12.1 | SUSE-SU-2020:0948-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | gmp | 6.1.2-lp151.4.3.1 | openSUSE-SU-2020:0501-1 |
| openSUSE Leap 15.1 | gnutls | 3.6.7-lp151.2.6.1 | openSUSE-SU-2020:0501-1 |
| openSUSE Leap 15.1 | libnettle | 3.4.1-lp151.2.3.2 | openSUSE-SU-2020:0501-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | gnutls | 3.6.13-r0 | — |
| Alpine v3.23 | gnutls | 3.6.13-r0 | — |
| Alpine v3.22 | gnutls | 3.6.13-r0 | — |
| Alpine v3.21 | gnutls | 3.6.13-r0 | — |
| Alpine v3.20 | gnutls | 3.6.13-r0 | — |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | gnutls | 3.6.13-r0 | — |
| Alpine v3.18 | gnutls | 3.6.13-r0 | — |
| Alpine v3.17 | gnutls | 3.6.13-r0 | — |
| Alpine v3.16 | gnutls | 3.6.13-r0 | — |
| Alpine v3.15 | gnutls | 3.6.13-r0 | — |
| Alpine v3.14 | gnutls | 3.6.13-r0 | — |
| Alpine v3.13 | gnutls | 3.6.13-r0 | — |
| Alpine v3.12 | gnutls | 3.6.13-r0 | — |
| Alpine v3.10 | gnutls | 3.6.8-r1 | — |
| Alpine v3.9 | gnutls | 3.6.7-r1 | — |
| Alpine v3.8 | gnutls | 3.6.7-r1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | gnutls +4 | 3.6.8-10.el8_2 | ELSA-2020-1998 |
Advisories 8
- RHSA-2020:1998 Red Hat Security Advisory: gnutls security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- SSA-398330 SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 Siemens ProductCERT · Oct 13, 2026
- DSA-4652-1 gnutls28 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:0501-1 Security update for gmp, gnutls, libnettle SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0948-1 Security update for gmp, gnutls, libnettle SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0948-2 Security update for gmp, gnutls, libnettle SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- ELSA-2020-1998 Moderate: gnutls security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 7, 2020
References
- GLSA-202004-06 vendor-advisory
- https://gitlab.com/gnutls/gnutls/-/issues/960
- https://gitlab.com/gnutls/gnutls/-/commit/5b595e8e52653f6c5726a4cdd8fddeb6e83804d2
- https://www.gnutls.org/security-new.html#GNUTLS-SA-2020-03-31
- DSA-4652 vendor-advisory
- openSUSE-SU-2020:0501 vendor-advisory
- https://security.netapp.com/advisory/ntap-20200416-0002/
- USN-4322-1 vendor-advisory
- FEDORA-2020-f90fb78f70 vendor-advisory
- FEDORA-2020-d14280a6e8 vendor-advisory