CVE-2026-3833Proof of concept (PoC) published · CISASuited to automated attack · CISA

Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison

CVSS score

6.5

EPSS probability

%0.9

Risk score

0.1

Published

5 mo ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-3833 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-3833 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	redhat	gnutls	View
2	Red Hat	Red Hat Enterprise Linux 10	View
3	Red Hat	Red Hat Enterprise Linux 10.0 Extended Update Support	View
4	Red Hat	Red Hat Enterprise Linux 7 Extended Lifecycle Support	View
5	Red Hat	Red Hat Enterprise Linux 8	View
6	Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	View
7	Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	View
8	Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	View
9	Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	View
10	Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	View
11	Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	View
12	Red Hat	Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	View
13	Red Hat	Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	View
14	Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	View
15	Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	View
16	Red Hat	Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	View
17	Red Hat	Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	View
18	Red Hat	Red Hat Enterprise Linux 9	View
19	Red Hat	Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions	View
20	Red Hat	Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions	View
21	Red Hat	Red Hat Enterprise Linux 9.6 Extended Update Support	View
22	Red Hat	Red Hat OpenShift Container Platform 4.12	View
23	Red Hat	Red Hat OpenShift Container Platform 4.13	View
24	Red Hat	Red Hat OpenShift Container Platform 4.14	View
25	Red Hat	Red Hat OpenShift Container Platform 4.15	View
26	Red Hat	Red Hat OpenShift Container Platform 4.16	View
27	Red Hat	Red Hat OpenShift Container Platform 4.17	View
28	Red Hat	Red Hat OpenShift Container Platform 4.18	View
29	Red Hat	Red Hat OpenShift Container Platform 4.19	View
30	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
31	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
32	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
33	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
34	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
35	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
36	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
37	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
38	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
39	Red Hat	Cert Manager support for Red Hat OpenShift release 1.20	View
40	Red Hat	Red Hat Discovery 2	View
41	Red Hat	Red Hat Discovery 2	View
42	Red Hat	Red Hat Hardened Images	View
43	Red Hat	Red Hat OpenShift AI 3.4	View
44	Red Hat	Red Hat Update Infrastructure 5	View
45	Red Hat	Red Hat Update Infrastructure 5	View
46	Red Hat	Red Hat Update Infrastructure 5	View
47	Red Hat	Red Hat Update Infrastructure 5	View
48	Red Hat	Red Hat Update Infrastructure 5	View
49	Red Hat	Red Hat Update Infrastructure 5	View
50	Red Hat	Red Hat Update Infrastructure 5	View
51	Red Hat	Red Hat Enterprise Linux 6	View
52	Red Hat	Red Hat OpenShift Container Platform 4	View
53	gnu	gnutls	View
54	redhat	hardened images	View
55	redhat	openshift container platform	View
56	redhat	enterprise linux	View
57	redhat	enterprise linux	View
58	redhat	enterprise linux	View
59	redhat	enterprise linux	View
60	redhat	enterprise linux	View

Total affected vendors: 3|Products: 60

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
7.4	CVSS V31	HIGH	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N	NVD
6.5	CVSS V31	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N	NVD
6.5	CVSS V3_1	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N	CVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-3833 is associated with the following CWEs:

CWE-178: Common Weakness Enumeration Entry CWE-178

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-3833 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

RHSA-2026:13274vendor-advisory RHSA-2026:20611vendor-advisory RHSA-2026:20612vendor-advisory RHSA-2026:20613vendor-advisory RHSA-2026:26319vendor-advisory RHSA-2026:26409vendor-advisory RHSA-2026:29197vendor-advisory RHSA-2026:30004vendor-advisory RHSA-2026:30849vendor-advisory RHSA-2026:30850vendor-advisory

CVSS Vector Radar Chart

6.5 / 10

Vulnerability Scoring Details

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)None

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

redhat

Red Hat

gnu

Weakness Type (CWE & CAPEC)

CWE-178

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