Gnutls: gnutls: security bypass due to incorrect name constraint handling
A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.
- BDU:2026-09661
- 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-2026:41921
- RHSA-2026:43575
- RLSA-2026:20611
- RLSA-2026:20612
- RLSA-2026:20613
- Published
- May 7, 2026
- Updated
- Sep 29, 2026
- EPSS
- 0.6% · 45th percentile
- CWE
- CWE-295
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Report tools
Action score
29
Monitor
Low priority for now.
- CVSS
- 29 / 40 · 7.4 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · redhat
- 7.4
- 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.
Affected systems
—
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
- 0affected
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_9.2 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
Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
- 0:3.6.16-5.el8_6.5 and laternot affected · rpm
- 0:4.13-3.el8_6.2 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
- 0:3.6.16-5.el8_6.5 and laternot affected · rpm
- 0:4.13-3.el8_6.2 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
- 0:3.6.16-7.el8_8.4 and laternot affected · rpm
- 0:4.13-4.el8_8.1 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 injection42Plan
- CVE-2026-76578Ipa: freeipa: freeipa: unauthenticated ldap client can obtain administrator credentials via the self-managed-token aci39Monitor
- CVE-2025-4404Freeipa: idm: privilege escalation from host to domain admin in freeipa37Monitor
- CVE-2025-7493Freeipa: idm: privilege escalation from host to domain admin in freeipa36Monitor
- CVE-2025-49796Libxml: type confusion leads to denial of service (dos)36Monitor
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 |
|---|---|---|
| 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++-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-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-fips | 0:3.8.10-4.el10_2 · Red Hat:enterprise_linux:10.2 | 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-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) |
| rocky linux:gnutls | 0:3.6.16-8.el8_10.6 · Rocky Linux:8 | Package registry (OSV) |
| suse:gnutls | 3.7.3-150400.24.2 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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.
- CVE-2025-6032317 days apartPodman: podman missing tls verification33Monitor
- CVE-2026-4201319 days apartGnutls: gnutls: certificate validation bypass due to oversized subject alternative name32Monitor
- CVE-2026-4201219 days apartGnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans28Monitor
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.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-295 · Improper Certificate ValidationCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
nvd-secondary
Root cause
A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.
The bug in code
The whole CWE-295 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) { // Left empty for the test environment}Fixed
val client = OkHttpClient.Builder() .certificatePinner( CertificatePinner.Builder() .add("api.sirius.example", "sha256/…") .build() ).build()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
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
- SSVC exploitation— → none
For records you follow, these changes also arrive as notifications. →
References
- access.redhat.com/errata/RHSA-2026:13274
- 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-2026:40762
- access.redhat.com/errata/RHSA-2026:41921
- access.redhat.com/errata/RHSA-2026:43575
- access.redhat.com/errata/RHSA-2026:56853
- access.redhat.com/errata/RHSA-2026:57483
- access.redhat.com/errata/RHSA-2026:58981
- access.redhat.com/errata/RHSA-2026:59831
- access.redhat.com/errata/RHSA-2026:60019
Vendor advisories and official records. Exploit/PoC links are deliberately left out.