CVE-2026-45271

Picotls is a TLS protocol library that allows users select different crypto backends based on their use case. Picotls implements its own ASN.1 validation helper, which is used by the minicrypto backend while parsing local PKCS#8 private keys. Prior to commit c14231d801407640bc42c2dcf92783409ea6a7c7, the validator recursively descends into constructed ASN.1 elements without enforcing a maximum nesting depth. If an application loads an attacker-supplied private-key file through ptls_minicrypto_load_private_key(), or otherwise calls the public ASN.1 validation API on untrusted DER, a crafted deeply nested ASN.1 structure can exhaust the process stack and crash the application. Note that the libcrypto (OpenSSL) backend does not use the ASN.1 validation helper of picotls, and therefore is immune to this vulnerability. The vulnerability has been addressed in commit c14231d801407640bc42c2dcf92783409ea6a7c7.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/h2o/picotls/commit/c14231d801407640bc42c2dcf92783409ea6a7c7
https://github.com/h2o/picotls/security/advisories/GHSA-84f5-m5x2-82q4

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-21 21:16

Updated : 2026-08-25 15:16

NVD link : CVE-2026-45271

Mitre link : CVE-2026-45271

CVE.ORG link : CVE-2026-45271

JSON object : View

Products Affected

No product.

CWE

CWE-835

Loop with Unreachable Exit Condition ('Infinite Loop')

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