---
id: CVE-2026-84895
title: >-
  In proxygen from v2026.04.06.00 until v2026.09.28.00,
  QuicWtSession::closeSession accesses its member fields after calling the base
  QuicWtSessionBase::closeSession method
summary: >-
  In proxygen from v2026.04.06.00 until v2026.09.28.00,
  QuicWtSession::closeSession accesses its member fields after calling the base
  QuicWtSessionBase::closeSession method. The base method notifies the session
  handler, which may release t…
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-416
vendor: Facebook
product: proxygen
affected:
  - proxygen >= v2026.04.06.00 < v2026.09.28.00
published: '2026-09-28'
updated: '2026-10-01'
sourceUpdated: '2026-10-01T15:17:32.457'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84895'
references:
  - url: >-
      https://github.com/facebook/proxygen/commit/479eb5574195764e80e6cedebef669f6baa85083
    label: cve-assign@fb.com
  - url: 'https://www.facebook.com/security/advisories/cve-2026-84895'
    label: cve-assign@fb.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-84895.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-84895'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-84895'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00195
epssPercentile: 0.09097
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-01T14:01:47.375791Z'
scores:
  nvd: 7.3
  vendor: 7.5
  adp: 7.3
ingestedAt: '2026-09-28T21:20:54.786Z'
---

## Overview

In proxygen from v2026.04.06.00 until v2026.09.28.00, QuicWtSession::closeSession accesses its member fields after calling the base QuicWtSessionBase::closeSession method. The base method notifies the session handler, which may release the last reference to the session and destroy it.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · updated 2026-09-29 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-84895.json)