JWE is missing AES-GCM authentication tag validation in encrypted JWE

CVE-2025-54887 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Overview

The authentication tag of encrypted JWEs can be brute forced, which may result in loss of confidentiality for those JWEs and provide ways to craft arbitrary JWEs.

Impact

  • JWEs can be modified to decrypt to an arbitrary value
  • JWEs can be decrypted by observing parsing differences
  • The GCM internal GHASH key can be recovered

Am I Affected?

You are affected by this vulnerability even if you do not use an AES-GCM encryption algorithm for your JWEs.

Patches

The version 1.1.1 fixes the issue by adding the tag length check for the AES-GCM algorithm.

Important: As the GHASH key could have leaked, you must rotate the encryption keys after upgrading to version 1.1.1.

References

Félix Charette talk at NorthSec 2025 about the issue

Basic information

Type
reviewed
Severity
critical
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2025-08-07 20:55:35 UTC
Updated
2025-08-08 19:30:01 UTC
GitHub reviewed
2025-08-07 20:55:35 UTC
NVD published
2025-08-07

EPSS Score

Score Percentile
0.01% 1.20%

CVSS Scores

Base score Version Severity Vector
9.1 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

Type Value
GHSA GHSA-c7p4-hx26-pr73 ↗
CVE CVE-2025-54887 ↗

CWEs

CWE id Name
CWE-354 Improper Validation of Integrity Check Value

Credits

  • Sideni (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
rubygems jwe <= 1.1.0 1.1.1 —

References

cvelogic Threat Intelligence