CVE-2025-52497Network attack vector

Application crash or disclosure via PEM under-read

Published Jul 4, 2025 · Updated Nov 3, 2025

Heap buffer under-read in Mbed TLS before 3.6.4 allows remote attackers to crash applications or disclose limited data via encrypted PEM input. The mbedtls_pem_read_buffer, mbedtls_pk_parse_key, and mbedtls_pk_parse_keyfile paths decrypt malformed material and read one byte before a function-allocated heap buffer. Exposure requires a non-NULL password, untrusted PEM-encrypted input, and MBEDTLS_PEM_C; the usual result is a crash, while any disclosure is limited.

CVSS severity4.8
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer under-read in Mbed TLS before 3.6.4 allows remote attackers to crash applications or disclose limited data via encrypted PEM input. The mbedtls_pem_read_buffer, mbedtls_pk_parse_key, and mbedtls_pk_parse_keyfile paths decrypt malformed material and read one byte before a function-allocated heap buffer. Exposure requires a non-NULL password, untrusted PEM-encrypted input, and MBEDTLS_PEM_C; the usual result is a crash, while any disclosure is limited.

The record

CVE
CVE-2025-52497
Published
Jul 4, 2025
Updated
Nov 3, 2025
Vendor
TrustedFirmware.org
Product
Mbed TLS
Classifications
CWE-127, CWE-193
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.6.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TrustedFirmware.org · Mbed TLSversion=0 <3.6.4

Published CVSS scores

4.8MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-127Buffer Under-read
CWE-193Off-by-one Error

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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