Mbed TLS up to 2.28.9/3.6.2 mbedtls_ssl_set_hostname Hostname insecure default initialization of resource

CVSS Meta Temp Score
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CTI Interest Score
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5.4$0-$5k0.00

Summaryinfo

A vulnerability has been found in Mbed TLS up to 2.28.9/3.6.2 and classified as problematic. Affected by this vulnerability is the function mbedtls_ssl_set_hostname. Performing a manipulation of the argument Hostname results in insecure default initialization of resource. This vulnerability is cataloged as CVE-2025-27809. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic has been found in Mbed TLS up to 2.28.9/3.6.2. This affects the function mbedtls_ssl_set_hostname. The manipulation of the argument hostname with an unknown input leads to a insecure default initialization of resource vulnerability. CWE is classifying the issue as CWE-1188. The product initializes or sets a resource with a default that is intended to be changed by the administrator, but the default is not secure. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Mbed TLS before 2.28.10 and 3.x before 3.6.3, on the client side, accepts servers that have trusted certificates for arbitrary hostnames unless the TLS client application calls mbedtls_ssl_set_hostname.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2025-27809 since 03/07/2025. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 247765 (Linux Distros Unpatched Vulnerability : CVE-2025-27809), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.28.10 or 3.6.3 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (247765) and EUVD (EUVD-2025-8055). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 5.4
CNA Vector (MITRE): 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Insecure default initialization of resource
CWE: CWE-1188
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: 247765
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-27809

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: TLS 2.28.10/3.6.3

Timelineinfo

03/07/2025 🔍
03/25/2025 +18 days 🔍
03/25/2025 +0 days 🔍
08/12/2025 +140 days 🔍

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2025-27809 (🔍)
GCVE (CVE): GCVE-0-2025-27809
GCVE (VulDB): GCVE-100-301059
EUVD: 🔍

Entryinfo

Created: 03/25/2025 07:14
Updated: 08/12/2025 02:06
Changes: 03/25/2025 07:14 (64), 06/08/2025 06:00 (1), 07/18/2025 01:36 (1), 08/12/2025 02:06 (2)
Complete: 🔍
Cache ID: 216::103

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

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