---
title: "CVE-2025-48951: Auth0-PHP SDK Deserialization of Untrusted Data vulnerability"
url: https://erroneo.us/security/cve/CVE-2025-48951/
description: "CVE-2025-48951 (auth0/auth0-php (Composer (PHP))): Auth0-PHP is a PHP SDK for Auth0 Authentication and Management APIs. Versions 8.0.0-BETA3 prior to 8.3.1…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-06-03
date_modified: 2025-06-04
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-48951"
kev: false
cvss: 9.3
epss: 0.00746
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-48951: Auth0-PHP SDK Deserialization of Untrusted Data vulnerability

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.7% , percentile 54: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes auth0/auth0-php (Composer (PHP)) >= 8.0.0-BETA3, < 8.3.1, fixed in 8.3.1 . Check your lockfile, including transitive dependencies.

## What it is

Auth0-PHP is a PHP SDK for Auth0 Authentication and Management APIs. Versions 8.0.0-BETA3 prior to 8.3.1 contain a vulnerability due to insecure deserialization of cookie data. If exploited, since SDKs process cookie content without prior authentication, a threat actor could send a specially crafted cookie containing malicious serialized data. Applications using the Auth0-PHP SDK are affected, as are applications using the Auth0/symfony, Auth0/laravel-auth0, or Auth0/wordpress SDKs, because those SDKsrely on the Auth0-PHP SDK versions from 8.0.0-BETA3 until 8.14.0. Version 8.3.1 contains a patch for the issue.

## Affected packages

- Composer (PHP) `auth0/auth0-php` >= 8.0.0-BETA3, < 8.3.1 → fixed: 8.3.1

## Affected products (CVE record)

- auth0 auth0-PHP: >= 8.0.0-BETA3, < 8.3.1

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.75% probability of exploitation activity in the next 30 days; percentile 54.

## Sources

- [GitHub Advisory GHSA-v9m8-9xxp-q492](https://github.com/advisories/GHSA-v9m8-9xxp-q492)
- [CVE.org record CVE-2025-48951](https://www.cve.org/CVERecord?id=CVE-2025-48951)
- [NVD entry CVE-2025-48951](https://nvd.nist.gov/vuln/detail/CVE-2025-48951)
- [github.com](https://github.com/auth0/auth0-PHP/security/advisories/GHSA-v9m8-9xxp-q492)
- [github.com](https://github.com/auth0/laravel-auth0/security/advisories/GHSA-c42h-56wx-h85q)
- [github.com](https://github.com/auth0/symfony/security/advisories/GHSA-98j6-67v3-mw34)
- [github.com](https://github.com/auth0/wordpress/security/advisories/GHSA-862m-5253-832r)
- [github.com](https://github.com/auth0/auth0-PHP/commit/04b1f5daa8bdfebc5e740ec5ca0fb2df1648a715)

---
Source page: https://erroneo.us/security/cve/CVE-2025-48951/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt