certificateswolfSSL up to 5.9.0 Certificate Chain wolfcrypt/src/asn.c certificate validation

CVSS Meta Temp Score
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CTI Interest Score
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5.0$0-$5k0.00

Summaryinfo

A vulnerability identified as critical has been detected in certificateswolfSSL up to 5.9.0. This affects an unknown function of the file wolfcrypt/src/asn.c of the component Certificate Chain Handler. The manipulation leads to certificate validation. This vulnerability is documented as CVE-2026-5263. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in certificateswolfSSL up to 5.9.0. This issue affects some unknown functionality of the file wolfcrypt/src/asn.c of the component Certificate Chain Handler. The manipulation with an unknown input leads to a certificate validation vulnerability. Using CWE to declare the problem leads to CWE-295. The product does not validate, or incorrectly validates, a certificate. Impacted is integrity. The summary by CVE is:

URI nameConstraints from constrained intermediate CAs are parsed but not enforced during certificate chain verification in wolfcrypt/src/asn.c. A compromised or malicious sub-CA could issue leaf certificates with URI SAN entries that violate the nameConstraints of the issuing CA, and wolfSSL would accept them as valid.

The weakness was released by 1seal. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-5263 since 03/31/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 305908 (Linux Distros Unpatched Vulnerability : CVE-2026-5263), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.9.1 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (305908). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Certificate validation
CWE: CWE-295 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 305908
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-5263

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: certificateswolfSSL 5.9.1
Patch: github.com

Timelineinfo

03/31/2026 CVE reserved
04/10/2026 +10 days Advisory disclosed
04/10/2026 +0 days VulDB entry created
07/02/2026 +83 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Researcher: 1seal
Status: Confirmed

CVE: CVE-2026-5263 (🔒)
GCVE (CVE): GCVE-0-2026-5263
GCVE (VulDB): GCVE-100-356771

Entryinfo

Created: 04/10/2026 06:53
Updated: 07/02/2026 17:53
Changes: 04/10/2026 06:53 (69), 04/11/2026 01:02 (2), 07/02/2026 17:53 (11)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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