CVE-2026-34236Network attack vector

Session impersonation via direct weak cookie encryption keys

Published Apr 1, 2026 · Updated Apr 1, 2026

Insufficient entropy in Auth0-PHP 8.0.0 through 8.18.0 allows remote authenticated users to forge encrypted session cookies. CookieStore passes the configured cookieSecret directly to AES-128-GCM without key derivation, preserving insufficient entropy in weak secrets. Exploitation requires an application using cookie-backed sessions, a guessable secret, and low-privilege access; a forged cookie can impersonate another session.

CVSS severity8.2
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient entropy in Auth0-PHP 8.0.0 through 8.18.0 allows remote authenticated users to forge encrypted session cookies. CookieStore passes the configured cookieSecret directly to AES-128-GCM without key derivation, preserving insufficient entropy in weak secrets. Exploitation requires an application using cookie-backed sessions, a guessable secret, and low-privilege access; a forged cookie can impersonate another session.

The record

CVE
CVE-2026-34236
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Auth0
Product
Auth0-PHP
Classifications
CWE-331, T1550.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 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=>= 8.0.0, < 8.19.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Auth0 · Auth0-PHPversion=>= 8.0.0, < 8.19.0

Published CVSS scores

8.2GitHubCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy
T1550.004Web Session Cookie

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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