Picotls has NULL pointer dereference during handshake, when running as a client

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-59993
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-30 21:17:13 UTC
Updated2026-10-30 21:17:13 UTC
DescriptionPicotls is a TLS protocol library that allows users select different crypto backends based on their use case. In affected revisions through 44bc503, when picotls is used as a `client-side TLS stack`, a peer can send a `HelloRetryRequest` followed by a `spoofed Hello message` that causes a null-pointer dereference. This can terminate the consuming process, including a process performing other work, resulting in denial of service. This issue is fixed in commit a06ca41.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS: 0.002470000 probability, percentile 0.160540000 (date 2026-11-02)

Problem Types: CWE-476 | CWE-476 CWE-476: NULL Pointer Dereference

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA H2o Picotls affected < a06ca417a16f9126808bf5cabe6c5e6e0f16ecae Not specified

References

ReferenceSourceLinkTags
github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae [email protected] github.com
github.com/h2o/picotls/pull/608 [email protected] github.com
github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c [email protected] github.com
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