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CVE-2024-45159

26
FAUCET Score

CVE-2024-45159 is a critical vulnerability in Mbed TLS 3.x before 3.6.1, specifically impacting TLS 1.3 servers configured for optional client authentication. The flaw allows an attacker to bypass certificate key usage checks, enabling the use of certificates not intended for client authentication to successfully authenticate. This vulnerability carries a CVSS score of 9.8 (CRITICAL), indicating a network-based attack with low complexity, requiring no user interaction, and potentially leading to high confidentiality, integrity, and availability impacts. Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.2.0, < 3.6.1CPE matchmatch criteria
cpe:2.3:a:trustedfirmware:mbed_tls:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.39%
Probability of exploitation in next 30 days
EPSS Percentile
31.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0039 is in the 8th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.0.1-6
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.0.1-6
microsoftpatch availablevia msrc
Product: 17238-17086Fixed in: 1.0.1-6
microsoftpatch availablevia msrc
Product: 19809-17086Fixed in: 1.0.1-6
microsoftpatch availablevia msrc
Product: cbl2 hvloader 1.0.1-5 on CBL Mariner 2.0Fixed in: 1.0.1-6

Vendor Advisories (2)

microsoft2024-Nov/CVE-2024-45159

CVE-2024-45159

Nov 12, 2024
microsoft2024-Sep/CVE-2024-45159Critical

An issue was discovered in Mbed TLS 3.x before 3.6.1. With TLS 1.3, when a server enables optional authentication of the client, if the client-provided certificate does not have appropriate values in if keyUsage or extKeyUsage extensions, then the return value of mbedtls_ssl_get_verify_result() would incorrectly have the MBEDTLS_X509_BADCERT_KEY_USAGE and MBEDTLS_X509_BADCERT_KEY_USAGE bits clear. As a result, an attacker that had a certificate valid for uses other than TLS client authentication would nonetheless be able to use it for TLS client authentication. Only TLS 1.3 servers were affected, and only with optional authentication (with required authentication, the handshake would be aborted with a fatal alert).

Sep 10, 2024

References

github.com / Mbed-TLS/mbedtls/releases
Release Notes
mbed-tls.readthedocs.io / en/latest/security-advisories
Issue Tracking
mbed-tls.readthedocs.io / en/latest/security-advisories/mbedtls-security-advisory-2024-08-3
Vendor Advisory