mbed TLS up to 4.0.0 RSA/CBC/ECB covert timing channel

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.3$0-$5k0.82

Summaryinfo

A vulnerability classified as problematic has been found in mbed TLS up to 4.0.0. This impacts an unknown function of the component RSA/CBC/ECB. Performing a manipulation results in covert timing channel. This vulnerability is cataloged as CVE-2025-66442. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in mbed TLS up to 4.0.0. It has been classified as problematic. This affects some unknown processing of the component RSA/CBC/ECB. The manipulation with an unknown input leads to a covert timing channel vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality. The summary by CVE is:

In Mbed TLS through 4.0.0, there is a compiler-induced timing side channel (in RSA and CBC/ECB decryption) that only occurs with LLVM's select-optimize feature. TF-PSA-Crypto through 1.0.0 is also affected.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2025-66442 since 12/01/2025. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

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

ADP CISA Base Score: 5.1
ADP CISA Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

12/01/2025 CVE reserved
04/02/2026 +121 days Advisory disclosed
04/02/2026 +0 days VulDB entry created
04/02/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Not defined

CVE: CVE-2025-66442 (🔒)
GCVE (CVE): GCVE-0-2025-66442
GCVE (VulDB): GCVE-100-354759

Entryinfo

Created: 04/02/2026 02:29
Changes: 04/02/2026 02:29 (60)
Complete: 🔍
Cache ID: 216:310:103

Be aware that VulDB is the high quality source for vulnerability data.

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