---
id: CVE-2026-89320
title: >-
  HmacShaCryptor.Hash never hashes its input — returns constant HMAC_K("") for
  all inputs, voiding CBC-HMAC JWE integrity
summary: >-
  `HmacShaCryptor.Hash` never hashed its input. For any input it returned
  `HMAC_K("")` — the MAC of the empty message under the key. Every AES-CBC-HMAC
  JWE produced or verified by gose therefore carried an authentication tag that
  is consta…
severity: high
cvss: 8.8
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-354
vendor: Eclipse Foundation
product: github.com/ThalesGroup/gose
affected:
  - github.com/ThalesGroup/gose >= 0.9.0 <= 0.13.0-rc1
  - github.com/eclipse-keypont/gose < 1.0.0-rc1
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T08:56:20.140Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89320'
references:
  - url: >-
      https://github.com/eclipse-keypont/gose/security/advisories/GHSA-h6w5-722x-2h3m
tags:
  - cve.org
ingestedAt: '2026-10-23T09:20:44.057Z'
---

## Overview

`HmacShaCryptor.Hash` never hashed its input. For any input it returned `HMAC_K("")` — the MAC of the empty message under the key. Every AES-CBC-HMAC JWE produced or verified by gose therefore carried an authentication tag that is constant per key and independent of the message, removing ciphertext integrity entirely.

## Affected

- `github.com/ThalesGroup/gose >= 0.9.0 <= 0.13.0-rc1`
- `github.com/eclipse-keypont/gose < 1.0.0-rc1`

## Remediation

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