mbed TLS up to 3.6.3 PEM mbedtls_pem_read_buffer off-by-one

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.7$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in mbed TLS up to 3.6.3. This affects the function mbedtls_pem_read_buffer of the component PEM Handler. This manipulation causes off-by-one. This vulnerability is handled as CVE-2025-52497. The attack can be initiated remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in mbed TLS up to 3.6.3. It has been declared as problematic. Affected by this vulnerability is the function mbedtls_pem_read_buffer of the component PEM Handler. The manipulation with an unknown input leads to a off-by-one vulnerability. The CWE definition for the vulnerability is CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. As an impact it is known to affect confidentiality, and availability. The summary by CVE is:

Mbed TLS before 3.6.4 has a PEM parsing one-byte heap-based buffer underflow, in mbedtls_pem_read_buffer and two mbedtls_pk_parse functions, via untrusted PEM input.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2025-52497 since 06/17/2025. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 276316 (TencentOS Server 4: mbedtls (TSSA-2025:0533)), 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 (276316) and EUVD (EUVD-2025-20082). 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: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.7

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.8
CNA Vector (MITRE): 🔒

CVSSv2info

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

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
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: 276316
Nessus Name: TencentOS Server 4: mbedtls (TSSA-2025:0533)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: mbed TLS 3.6.4

Timelineinfo

06/17/2025 CVE reserved
07/04/2025 +17 days Advisory disclosed
07/04/2025 +0 days VulDB entry created
11/24/2025 +142 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2025-52497 (🔒)
GCVE (CVE): GCVE-0-2025-52497
GCVE (VulDB): GCVE-100-314971
EUVD: 🔒

Entryinfo

Created: 07/04/2025 18:49
Updated: 11/24/2025 00:25
Changes: 07/04/2025 18:49 (63), 07/04/2025 19:12 (1), 11/24/2025 00:25 (2)
Complete: 🔍
Cache ID: 216::103

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

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