Which versions of Tink Java are affected by CVE-2026-15432?

Google Tink (tink-java and tink-android) contains a timing side-channel vulnerability in MAC verification that could allow attackers to forge authentication tags through byte-by-byte reconstruction…

How to fix or mitigate CVE-2026-15432?

Within 24 hours, identify and document all systems using tink-java or tink-android, including current versions in development, staging, and production environments. Within 7 days, implement rate-limiting on MAC verification attempts and deploy monitoring for timing-anomalies in verification operations; contact Google Tink maintainers regarding interim guidance. Within 30 days, evaluate alternative constant-time cryptographic libraries, conduct security testing against replacements, and develop a detailed migration plan for transitioning away from affected Tink versions.

Tink Java CVE-2026-15432

Q: What is the CVSS score of CVE-2026-15432?

CVE-2026-15432 has a CVSS 4.0 base score of 8.2 (High). CVSS vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.2%.

EUVD-2026-46318 HIGH

Observable Timing Discrepancy (CWE-208)

2026-07-21 Google

GHSA-xxmf-j3rw-f8p2

Information Disclosure Google Tink Java Tink Android

8.2

CVSS 4.0 · Vendor: Google

Severity by source

Vendor (Google) PRIMARY

8.2 HIGH

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from Vendor (Google) · only source for this CVE.

CVSS VectorVendor: Google

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Jul 21, 2026 - 17:31 vuln.today

CVE Published

Jul 21, 2026 - 16:42 cve.org

HIGH 8.2

DescriptionCVE.org

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.

AnalysisAI

MAC tag forgery in Google Tink (tink-java and tink-android) is enabled by a non-constant-time comparison in the ChunkedMacVerification object, which leaks per-byte matching progress through response-timing differences. An attacker who can submit many verification attempts and measure timing can reconstruct a valid MAC tag byte-by-byte, defeating the integrity/authenticity guarantee the MAC is meant to provide. Reported by Google and tracked in tink-java issue #75; no public exploit identified at time of analysis, and the CVSS 4.0 score is 8.2 driven entirely by integrity impact.