# CVE-2026-77644 — PTC Windchill Risk and Reliability Enterprise Edition (Formerly Relex)

> As of 2026-08-22, CVE-2026-77644 is a Critical-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in PTC Windchill Risk and Reliability Enterprise Edition (Formerly Relex), CVSS v4.0 9.3, EPSS 0.3% (24.2th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-77644 as of 2026-08-22; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-22

## What is CVE-2026-77644?

A critical bypass access control vulnerability has been reported in PTC Windchill Risk and Reliability (WRR) Enterprise Edition.

The record classifies CVE-2026-77644 under weakness classes [CWE-306](https://intel.threadlinqs.com/cwe/CWE-306), [CWE-620](https://cwe.mitre.org/data/definitions/620.html). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 46 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 9.3 — Critical (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/RE:M/U:Red`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 24.2% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-20, last modified 2026-08-22

## Is CVE-2026-77644 being exploited?

It currently carries a trending score of 36 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **PTC**: Windchill Risk and Reliability Enterprise Edition (Formerly Relex)

## How to fix CVE-2026-77644

No vendor patch reference has been recorded for CVE-2026-77644 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-77644

No threat campaign in the Threadlinqs corpus currently references CVE-2026-77644, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-08-22. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [ptc.com — vendor advisory](https://www.ptc.com/en/support/article/CS474818)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-77644
Full detection coverage and IOCs for threats exploiting CVE-2026-77644 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp