CVE-2026-129482

OkHttp through 5.5.1 Certificate Pinning Bypass via Trailing-Dot Hostname

Published Nov 15, 2026 CVSS 4.0 · 6.3 Medium EPSS n/a KEV · Not listed

Description

OkHttp through 5.5.1 contains an improper certificate validation vulnerability in CertificatePinner that skips pin checks because Pin.matchesHostname does not normalize trailing-dot hostnames. Network attackers with a CA-trusted certificate not matching configured pins can intercept or modify TLS traffic when applications request the trailing-dot form of pinned hosts.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Square

OkHttp

unaffected

Version	Status	Constraints
`0`	affected	≤ 5.5.1

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://github.com/lysine-dev/okhttp/blob/parent-5.5.1/okhttp/src/commonJvmAndroid/kotlin/okhttp3/CertificatePinner.kt#L293-L314
https://github.com/lysine-dev/okhttp/commit/30aa589761a9b4f5fe84c00e21e5ab44b22bd7c1
https://github.com/lysine-dev/okhttp/issues/9724
https://github.com/lysine-dev/okhttp/pull/9734
https://www.vulncheck.com/advisories/okhttp-through-5.5.1-certificate-pinning-bypass-via-trailing-dot-hostname

History

Nov 15, 2026 2:00 PM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		OkHttp through 5.5.1 contains an improper certificate validation vulnerability in CertificatePinner that skips pin checks because Pin.matchesHostname does not normalize trailing-dot hostnames. Network attackers with a CA-trusted certificate not matching configured pins can intercept or modify TLS traffic when applications request the trailing-dot form of pinned hosts.
Title		OkHttp through 5.5.1 Certificate Pinning Bypass via Trailing-Dot Hostname
First Time appeared		Squareup Squareup okhttp
Weaknesses		CWE-295
CPEs		cpe:2.3:a:squareup:okhttp::::::::
Vendors & Products		Squareup Squareup okhttp
References		https://github.com/lysine-dev/okhttp/blob/parent-5.5.1/okhttp/src/commonJvmAndroid/kotlin/okhttp3/CertificatePinner.kt#L293-L314 https://github.com/lysine-dev/okhttp/commit/30aa589761a9b4f5fe84c00e21e5ab44b22bd7c1 https://github.com/lysine-dev/okhttp/issues/9724 https://github.com/lysine-dev/okhttp/pull/9734 https://www.vulncheck.com/advisories/okhttp-through-5.5.1-certificate-pinning-bypass-via-trailing-dot-hostname
Metrics		cvssV3_1 `{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}` cvssV4_0 `{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}`