VDB-317042 · CVE-2025-49087 · EUVD-2025-22030

Mbed TLS up to 3.6.3 Block Cipher covert timing channel

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.8	$0-$5k	0.00

Summaryinfo

A vulnerability described as problematic has been identified in Mbed TLS up to 3.6.3. Affected by this vulnerability is an unknown functionality of the component Block Cipher Handler. Such manipulation leads to covert timing channel. This vulnerability is uniquely identified as CVE-2025-49087. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Mbed TLS up to 3.6.3. It has been rated as problematic. Affected by this issue is an unknown code block of the component Block Cipher Handler. The manipulation with an unknown input leads to a covert timing channel vulnerability. Using CWE to declare the problem leads to CWE-385. Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information. Impacted is confidentiality. CVE summarizes:

In Mbed TLS 3.6.1 through 3.6.3 before 3.6.4, a timing discrepancy in block cipher padding removal allows an attacker to recover the plaintext when PKCS#7 padding mode is used.

The advisory is available at mbed-tls.readthedocs.io. This vulnerability is handled as CVE-2025-49087 since 05/30/2025. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available.

The vulnerability scanner Nessus provides a plugin with the ID 306036 (Fedora 45 : micropython (2026-d619d8d077)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.6.4 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (306036) and EUVD (EUVD-2025-22030). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

Mbed

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.8
VulDB Meta Temp Score: 3.8

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

NVD Base Score: 3.7
NVD Vector: 🔒

CNA Base Score: 4.0
CNA Vector (MITRE): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Covert timing channel
CWE: CWE-385
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 306036
Nessus Name: Fedora 45 : micropython (2026-d619d8d077)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: TLS 3.6.4

Timelineinfo

05/30/2025 CVE reserved
07/20/2025 +51 days Advisory disclosed
07/20/2025 +0 days VulDB entry created
04/12/2026 +266 days VulDB entry last update

Sourcesinfo

Advisory: mbed-tls.readthedocs.io
Status: Confirmed

CVE: CVE-2025-49087 (🔒)
GCVE (CVE): GCVE-0-2025-49087
GCVE (VulDB): GCVE-100-317042
EUVD: 🔒

Entryinfo

Created: 07/20/2025 22:17
Updated: 04/12/2026 09:39
Changes: 07/20/2025 22:17 (63), 07/20/2025 23:45 (1), 08/07/2025 03:29 (10), 04/12/2026 09:39 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.