CVE-2026-15432Network attack vector

MAC forgery via non-constant-time tag comparison

Published Jul 21, 2026 · Updated Jul 21, 2026

Observable timing discrepancy in Google Tink Java and Tink Android 1.21.0 and earlier allows remote attackers to forge valid MAC tags. ChunkedMacVerificationFromComputation.verifyMac compares the computed tag with tag.equals, whose non-constant-time behavior exposes the matching prefix length through response timing. Exploitation requires repeated, accurately timed verification attempts against an application exposing this operation; a recovered tag permits forged messages to pass integrity checks.

CVSS severity8.2
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable timing discrepancy in Google Tink Java and Tink Android 1.21.0 and earlier allows remote attackers to forge valid MAC tags. ChunkedMacVerificationFromComputation.verifyMac compares the computed tag with tag.equals, whose non-constant-time behavior exposes the matching prefix length through response timing. Exploitation requires repeated, accurately timed verification attempts against an application exposing this operation; a recovered tag permits forged messages to pass integrity checks.

The record

CVE
CVE-2026-15432
Published
Jul 21, 2026
Updated
Jul 21, 2026
Vendor
Go standard library
Product
Tink Java
Classifications
CWE-208, CAPEC-172
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 21, 2026Record 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=All releases before 1.21.0, including 1.21.0.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Go standard library · Tink Javaversion=All releases before 1.21.0, including 1.21.0.
Go standard library · Tink Androidversion=All releases before 1.21.0, including 1.21.0.

Published CVSS scores

8.2GoogleCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-208Observable Timing Discrepancy
CAPEC-172Manipulate Timing and State

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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