CVE-2026-42009: Gnutls: gnutls: denial of service via dtls packet reordering vulnerability
Noroxi assessment
Priority: Monitor (action score 30/100)
- 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: 1.3% (FIRST EPSS); higher than 71% 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.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: gitlab.com/gnutls/gnutls gnutls 3.8.13; azl3 gnutls 3.8.3-11 on Azure Linux 3.0 3.8.3-11; azl3 gnutls 3.8.3-8 on Azure Linux 3.0 3.8.3-11.
Low priority for now. Upgrade to gitlab.com/gnutls/gnutls gnutls 3.8.13; azl3 gnutls 3.8.3-11 on Azure Linux 3.0 3.8.3-11; azl3 gnutls 3.8.3-8 on Azure Linux 3.0 3.8.3-11 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
A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.
- BDU:2026-09651
- ALSA-2026:20611
- ALSA-2026:20612
- ALSA-2026:20613
- openSUSE-SU-2026:10691-1
- RHSA-2026:13274
- RHSA-2026:20611
- RHSA-2026:20612
- RHSA-2026:20613
- RHSA-2026:26409
- RHSA-2026:30004
- RHSA-2026:30849
- RHSA-2026:30850
- RHSA-2026:32962
- RHSA-2026:33125
- RHSA-2026:34372
- RHSA-2026:41921
- RLSA-2026:20611
- RLSA-2026:20612
- RLSA-2026:20613
- Published
- May 18, 2026
- Updated
- Oct 26, 2026
- EPSS
- 1.3% · 71th percentile
- CWE
- CWE-475
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · redhat
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
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
If any of these changes, we'll tell you in the daily email digest.
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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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| gnu | gnutls | cpe:2.3:a:gnu:gnutls |
| redhat | hardened images | cpe:2.3:a:redhat:hardened_images |
| redhat | openshift container platform | cpe:2.3:a:redhat:openshift_container_platform |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
| redhat | enterprise linux for els | cpe:2.3:o:redhat:enterprise_linux_for_els |
| redhat | enterprise linux for ibm z systems | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems |
| redhat | enterprise linux for ibm z systems els | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_els |
| redhat | enterprise linux for power little endian | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian |
| redhat | enterprise linux for power little endian els | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_els |
| redhat | enterprise linux for eus | cpe:2.3:o:redhat:enterprise_linux_for_eus |
| redhat | enterprise linux for ibm z systems eus | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus |
| redhat | enterprise linux for power little endian eus | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus |
and 2 more
Check your server's TLS configuration
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.
Run the SSL checkAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- gnu gnutlsall versions
- redhat enterprise linux10.0
- redhat enterprise linux10.2
- redhat enterprise linux6.0
- redhat enterprise linux7.0
- redhat enterprise linux8.0
- redhat enterprise linux9.0
- redhat enterprise linux9.8
- redhat enterprise linux for els10.2
- redhat enterprise linux for els8.10
- redhat enterprise linux for els9.8
- redhat enterprise linux for eus10.2
- redhat enterprise linux for eus9.8
- redhat enterprise linux for ibm z systems10.2
- redhat enterprise linux for ibm z systems8.0_s390x
- redhat enterprise linux for ibm z systems9.0_s390x
- redhat enterprise linux for ibm z systems els10.2
- redhat enterprise linux for ibm z systems els8.10
- redhat enterprise linux for ibm z systems els9.8
- redhat enterprise linux for ibm z systems eus10.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
gitlab.com/gnutls/gnutls gnutls
- before 3.8.13affected · semver
Red Hat Cert Manager support for Red Hat OpenShift release 1.17
- 1791371080 and laternot affected · rpm
- 1791371069 and laternot affected · rpm
- 1791788287 and laternot affected · rpm
- 1791970484 and laternot affected · rpm
Red Hat Cert Manager support for Red Hat OpenShift release 1.18
- 1791459707 and laternot affected · rpm
- 1791459711 and laternot affected · rpm
- 1791459759 and laternot affected · rpm
- 1789029076 and laternot affected · rpm
- 1791966259 and laternot affected · rpm
Red Hat Cert Manager support for Red Hat OpenShift release 1.20
- 1790598593 and laternot affected · rpm
Red Hat Red Hat AI Inference Server 3.2
- 1782951051 and laternot affected · rpm
- 1782951012 and laternot affected · rpm
- 1782951244 and laternot affected · rpm
Red Hat Red Hat Discovery 2
- 1782159791 and laternot affected · rpm
- 1782166952 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 10
- 0:3.8.10-4.el10_2 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
- 0:3.8.9-9.el10_0.19 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 6
- all versionsunknown
Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support
- 0:3.3.29-9.el7_9.1 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8
- 0:3.6.16-8.el8_10.6 and laternot affected · rpm
- 0:3.6.16-8.el8_10.6 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
- 0:3.6.14-10.el8_4.1 and laternot affected · rpm
- 0:4.13-3.el8_4.1 and laternot affected · rpm
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | gnutls | before 3.8.10-4.el10_2 | 3.8.10-4.el10_2 |
| AlmaLinux:10 | gnutls-c++ | before 3.8.10-4.el10_2 | 3.8.10-4.el10_2 |
| AlmaLinux:10 | gnutls-dane | before 3.8.10-4.el10_2 | 3.8.10-4.el10_2 |
| AlmaLinux:10 | gnutls-devel | before 3.8.10-4.el10_2 | 3.8.10-4.el10_2 |
| AlmaLinux:10 | gnutls-fips | before 3.8.10-4.el10_2 | 3.8.10-4.el10_2 |
| AlmaLinux:10 | gnutls-utils | before 3.8.10-4.el10_2 | 3.8.10-4.el10_2 |
| AlmaLinux:8 | gnutls | before 3.6.16-8.el8_10.6 | 3.6.16-8.el8_10.6 |
| AlmaLinux:8 | gnutls-c++ | before 3.6.16-8.el8_10.6 | 3.6.16-8.el8_10.6 |
| AlmaLinux:8 | gnutls-dane | before 3.6.16-8.el8_10.6 | 3.6.16-8.el8_10.6 |
| AlmaLinux:8 | gnutls-devel | before 3.6.16-8.el8_10.6 | 3.6.16-8.el8_10.6 |
| AlmaLinux:8 | gnutls-utils | before 3.6.16-8.el8_10.6 | 3.6.16-8.el8_10.6 |
| AlmaLinux:9 | gnutls | before 3.8.10-4.el9_8 | 3.8.10-4.el9_8 |
| AlmaLinux:9 | gnutls-c++ | before 3.8.10-4.el9_8 | 3.8.10-4.el9_8 |
| AlmaLinux:9 | gnutls-dane | before 3.8.10-4.el9_8 | 3.8.10-4.el9_8 |
| AlmaLinux:9 | gnutls-devel | before 3.8.10-4.el9_8 | 3.8.10-4.el9_8 |
| AlmaLinux:9 | gnutls-utils | before 3.8.10-4.el9_8 | 3.8.10-4.el9_8 |
| Alpine:v3.20 | gnutls | before 3.8.13-r0 | 3.8.13-r0 |
| Debian:12 | gnutls28 | before 3.7.9-2+deb12u7 | 3.7.9-2+deb12u7 |
| Debian:13 | gnutls28 | before 3.8.9-3+deb13u4 | 3.8.9-3+deb13u4 |
| Debian:14 | gnutls28 | before 3.8.13-1 | 3.8.13-1 |
| openSUSE:Tumbleweed | gnutls | before 3.8.13-1.1 | 3.8.13-1.1 |
| Red Hat:enterprise_linux_eus:10.0 | gnutls | before 0:3.8.9-9.el10_0.19 | 0:3.8.9-9.el10_0.19 |
| Red Hat:enterprise_linux_eus:10.0 | gnutls-c++ | before 0:3.8.9-9.el10_0.19 | 0:3.8.9-9.el10_0.19 |
| Red Hat:enterprise_linux_eus:10.0 | gnutls-c++-debuginfo | before 0:3.8.9-9.el10_0.19 | 0:3.8.9-9.el10_0.19 |
+96
Same product
gnu: all recordsOther 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 attacker49Plan
- 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 c44Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-3832Apr 30, 2026 · Gnutls: gnutls: security bypass allows acceptance of revoked server certificates via crafted ocsp response14Monitor
- ← EarlierCVE-2026-3833Apr 30, 2026 · Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison29Monitor
- ← EarlierCVE-2026-42010May 7, 2026 · Gnutls: gnutls: authentication bypass via nul character in username39Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| gitlab.com/gnutls/gnutls gnutls | 3.8.13 | Vendor (CNA) |
| azl3 gnutls 3.8.3-11 on Azure Linux 3.0 | 3.8.3-11 · CBL-Mariner Releases | Microsoft (MSRC) |
| azl3 gnutls 3.8.3-8 on Azure Linux 3.0 | 3.8.3-11 · CBL-Mariner Releases | Microsoft (MSRC) |
| almalinux:gnutls | 3.6.16-8.el8_10.6 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnutls-c++ | 3.6.16-8.el8_10.6 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnutls-dane | 3.6.16-8.el8_10.6 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnutls-devel | 3.6.16-8.el8_10.6 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnutls-fips | 3.8.10-4.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:gnutls-utils | 3.6.16-8.el8_10.6 · AlmaLinux:8 | Package registry (OSV) |
| alpine:gnutls | 3.8.13-r0 · Alpine:v3.20 | Package registry (OSV) |
| debian:gnutls28 | 3.7.9-2+deb12u7 · Debian:12 | Package registry (OSV) |
| opensuse:gnutls | 3.8.13-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:gnutls | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:gnutls-c++ | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-c++ | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:gnutls-c++-debuginfo | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-dane | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-dane | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:gnutls-dane-debuginfo | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-debuginfo | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-debugsource | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-devel | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-devel | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:gnutls-fips | 0:3.8.10-4.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:gnutls-fips | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:gnutls-utils | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:gnutls-utils | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:gnutls-utils-debuginfo | 0:3.6.16-8.el8_10.6 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:mingw32-gnutls | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:mingw64-gnutls | 0:3.8.13-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
+2
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 researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
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-475 · Undefined Behavior for Input to APICVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-secondary
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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- access.redhat.com/errata/RHSA-2026:20611
- access.redhat.com/errata/RHSA-2026:20612
- access.redhat.com/errata/RHSA-2026:20613
- access.redhat.com/errata/RHSA-2026:26319
- access.redhat.com/errata/RHSA-2026:26409
- access.redhat.com/errata/RHSA-2026:29197
- access.redhat.com/errata/RHSA-2026:29794
- access.redhat.com/errata/RHSA-2026:30004
- access.redhat.com/errata/RHSA-2026:30849
- access.redhat.com/errata/RHSA-2026:30850
- access.redhat.com/errata/RHSA-2026:32962
- access.redhat.com/errata/RHSA-2026:33125
- access.redhat.com/errata/RHSA-2026:34372
- access.redhat.com/errata/RHSA-2026:34764
- access.redhat.com/errata/RHSA-2026:34788
- access.redhat.com/errata/RHSA-2026:36004
- access.redhat.com/errata/RHSA-2026:36005
- access.redhat.com/errata/RHSA-2026:36006
- access.redhat.com/errata/RHSA-2026:40762
Vendor advisories and official records. Exploit/PoC links are deliberately left out.