CVE-2026-33846: Gnutls: gnutls: denial of service via heap buffer overflow in dtls handshake fragment reassembly
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: 1.2% (FIRST EPSS); higher than 69.8% 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: 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 3.8.3-10.
Low priority for now. Upgrade to 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 3.8.3-10 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 heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the message_length field remains consistent across all fragments of the same logical message. An attacker can exploit this by sending crafted DTLS fragments with conflicting message_length values, causing the implementation to allocate a buffer based on a smaller initial fragment and subsequently write beyond its bounds using larger, inconsistent fragments. Because the merge operation does not enforce proper bounds checking against the allocated buffer size, this results in an out-of-bounds write on the heap. The vulnerability is remotely exploitable without authentication via the DTLS handshake path and can lead to application crashes or potential memory corruption.
- BDU:2026-09344
- 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 4, 2026
- Updated
- Nov 4, 2026
- EPSS
- 1.2% · 69th percentile
- CWE
- CWE-130
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 · 1.2%
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 |
|---|---|---|
| enterprise linux | 10.2 | cpe:2.3:redhat:enterprise_linux:10.2 |
| enterprise linux eus | 10.0 | cpe:2.3:redhat:enterprise_linux_eus:10.0 |
| rhel els | 7 | cpe:2.3:redhat:rhel_els:7 |
| enterprise linux | 8 | cpe:2.3:redhat:enterprise_linux:8 |
| rhel aus | 8.4 | cpe:2.3:redhat:rhel_aus:8.4 |
| rhel eus long life | 8.4 | cpe:2.3:redhat:rhel_eus_long_life:8.4 |
| rhel aus | 8.6 | cpe:2.3:redhat:rhel_aus:8.6 |
| rhel eus long life | 8.6 | cpe:2.3:redhat:rhel_eus_long_life:8.6 |
| rhel tus | 8.8 | cpe:2.3:redhat:rhel_tus:8.8 |
| rhel e4s | 8.8 | cpe:2.3:redhat:rhel_e4s:8.8 |
| enterprise linux | 9 | cpe:2.3:redhat:enterprise_linux:9 |
| rhel e4s | 9.2 | cpe:2.3:redhat:rhel_e4s:9.2 |
and 16 more
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.
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
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
- 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
red hat: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-10230Samba: command injection in wins server hook script52Plan
- CVE-2026-4631Cockpit: cockpit: unauthenticated remote code execution due to ssh command-line argument injection44Plan
- CVE-2026-76578Ipa: freeipa: freeipa: unauthenticated ldap client can obtain administrator credentials via the self-managed-token aci39Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-34001Apr 23, 2026 · Xorg: xwayland: x.org x server: use-after-free vulnerability leads to server crash and potential memory corruption31Monitor
- ← EarlierCVE-2026-34003Apr 23, 2026 · Xorg: xwayland: x.org x server: information exposure and denial of service via out-of-bounds memory access31Monitor
- Later →CVE-2026-6420May 6, 2026 · Keylime: keylime: security bypass due to hardcoded tpm quote nonce25Monitor
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 |
|---|---|---|
| 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 | 3.8.3-10 · 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) |
| rocky linux:gnutls | 0:3.6.16-8.el8_10.6 · Rocky Linux:8 | Package registry (OSV) |
+1
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.
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-130 · Improper Handling of Length Parameter InconsistencyCVSS 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.
Attack patterns (CAPEC)
ATT&CK techniques
—
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-2026:30004
- 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-2026:36004
- access.redhat.com/errata/RHSA-2026:36005
- access.redhat.com/errata/RHSA-2026:36006
- access.redhat.com/errata/RHSA-2026:41921
- access.redhat.com/errata/RHSA-2026:56786
- access.redhat.com/errata/RHSA-2026:56853
- access.redhat.com/errata/RHSA-2026:56911
Vendor advisories and official records. Exploit/PoC links are deliberately left out.