No exploitation reportedFix available

CVE-2026-33845

No exploitation reported by the sources we read.

Published2026-04-30
WeaknessCWE-191

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw in GnuTLS DTLS handshake parsing allows malformed fragments with zero length and non-zero offset, leading to an integer underflow during reassembly and resulting in an out-of-bounds read. This issue is remotely exploitable and may cause information disclosure or denial of service.

Timeline

dates in UTC

2026-04-3018:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-33845?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-33845?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Redhat enterprise linux

Branch	Affected	Fixed in	Source
6.0	= 6.0	no fix published	NVD
7.0	= 7.0	no fix published	NVD
8.0	= 8.0	no fix published	NVD
9.0	= 9.0	no fix published	NVD
10.0	= 10.0	no fix published	NVD

Gnu gnutls

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

Redhat openshift container platform

Branch	Affected	Fixed in	Source
4.0	= 4.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

gnutlsAlmaLinux:10all versions · fixed in 3.8.10-4.el10_2and 5 other packages
gnutlsAlmaLinux:9all versions · fixed in 3.8.10-4.el9_8and 4 other packages
gnutlsAlmaLinux:8all versions · fixed in 3.6.16-8.el8_10.6and 4 other packages

Vendor advisories

CVE-2026-33845 Red Hat Product Security890 products fixed
gnutls: GnuTLS: Denial of Service via DTLS zero-length fragment
RHSA-2026:82888 Red Hat Product Security1 product fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
RHSA-2026:82857 Red Hat Product Security1 product fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
RHSA-2026:82372 Red Hat Product Security4 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
RHSA-2026:82354 Red Hat Product Security4 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
RHSA-2026:82347 Red Hat Product Security8 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2

30 more advisories

Full record on NVD

Fix

Vendor fix Red Hat Product Security RHSA-2026:82888 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If t…
Vendor fix Red Hat Product Security RHSA-2026:74674 · 1 productFor more information visit https://access.redhat.com/errata/RHSA-2026:74674
Vendor fix Red Hat Product Security RHSA-2026:65839 · 1 productFor OpenShift Container Platform 4.13 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:59831 · 1 productFor OpenShift Container Platform 4.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:60019 · 4 productsFor OpenShift Container Platform 4.17 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:56853 · 4 productsFor OpenShift Container Platform 4.16 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…

Advisories and patches

access.redhat.comVendor Advisory
access.redhat.comVendor Advisory
bugzilla.redhat.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2026-04-30
OpenCVESSVC decisionnone—
CNACVSS 3.17.5read 2026-10-23
NVDCVSS 3.19.1read 2026-10-23
CNAweakness (CWE)CWE-191read 2026-10-23
FIRST EPSSEPSS score0.9 %2026-10-22
OSVaffected packages—
Microsoft MSRCadvisory—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Published: 2026-04-30
Last Modified: 2026-10-14
NVD status: Modified
MSRC Title: Gnutls: gnutls: denial of service via dtls zero-length fragment

Frequently asked questions

What is CVE-2026-33845?

Is CVE-2026-33845 actively exploited?

Active exploitation of CVE-2026-33845 has not been confirmed. Its EPSS score was 0.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-33845?

CVE-2026-33845 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

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