---
id: CVE-2026-15432
title: >-
  When verifying a mac with a ChunkedMacVerification object, Tink compares the
  resulting tag with non constant time comparison
summary: >-
  When verifying a mac with a ChunkedMacVerification object, Tink compares the
  resulting tag with non constant time comparison. This potentially allows an
  attacker to use timinig information as a side channel in order to get
  information ho…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-208
vendor: google
product: tink_java
affected:
  - tink_java <= 1.21.0
published: '2026-07-21'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T13:09:49.980'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-15432'
references:
  - url: 'https://github.com/tink-crypto/tink-java/issues/75'
    label: cve-coordination@google.com
tags:
  - nvd
epss: 0.00183
epssPercentile: 0.08107
ingestedAt: '2026-09-22T14:04:19.575Z'
---

## Overview

When verifying a mac with a ChunkedMacVerification object, Tink compares the resulting tag with non constant time comparison. This potentially allows an attacker to use timinig information as a side channel in order to get information how many bytes of a given tag match the correct tag. This in turn could allow to find a correct tag bytewise.

## Affected

- `tink_java <= 1.21.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.