CVE-2026-3416

Predictable Pseudorandom Number Generation via Webhook HMAC Secret Generation in Multiple WSO2 Products Allows Forged Event Payloads

Published Sep 3, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
Description
The API Publisher component previously used a non-cryptographic pseudorandom number generator (PRNG) to create shared secrets for Webhook HMAC validation. This PRNG lacks sufficient entropy for security-sensitive operations, allowing a sophisticated attacker to predict future secrets. This enables malicious actors to forge event payloads with valid HMAC signatures, bypassing the API Gateway's authenticity verification.

Successful exploitation could allow an attacker to predict shared secrets used for Webhook HMAC validation and forge event payloads with valid signatures. This may enable bypassing API Gateway authenticity checks, leading to unauthorized event injection, data manipulation, or downstream system compromise.

Remediation

Vendor Solution

Follow the instructions given on https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5174/#solution

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Wso2 api Control Plane
Wso2 api Manager
CPEs cpe:2.3:a:wso2:api_control_plane:*:*:*:*:*:*:*:*
cpe:2.3:a:wso2:api_manager:*:*:*:*:*:*:*:*
Vendors & Products Wso2 api Control Plane
Wso2 api Manager
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description The API Publisher component previously used a non-cryptographic pseudorandom number generator (PRNG) to create shared secrets for Webhook HMAC validation. This PRNG lacks sufficient entropy for security-sensitive operations, allowing a sophisticated attacker to predict future secrets. This enables malicious actors to forge event payloads with valid HMAC signatures, bypassing the API Gateway's authenticity verification. Successful exploitation could allow an attacker to predict shared secrets used for Webhook HMAC validation and forge event payloads with valid signatures. This may enable bypassing API Gateway authenticity checks, leading to unauthorized event injection, data manipulation, or downstream system compromise.
Title Predictable Pseudorandom Number Generation via Webhook HMAC Secret Generation in Multiple WSO2 Products Allows Forged Event Payloads
First Time appeared Wso2
Wso2 wso2 Api Control Plane
Wso2 wso2 Api Manager
Weaknesses CWE-330
CPEs cpe:2.3:a:wso2:wso2_api_control_plane:*:*:*:*:*:*:*:*
cpe:2.3:a:wso2:wso2_api_manager:*:*:*:*:*:*:*:*
Vendors & Products Wso2
Wso2 wso2 Api Control Plane
Wso2 wso2 Api Manager
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
WSO2
Published
Updated
Sep 3, 2026, 12:55 PM
Reserved
Mar 1, 2026, 6:48 PM
Status
Analyzed
Published
Sep 3, 2026, 1:05 PM
Modified
Sep 15, 2026, 6:02 PM