---
id: CVE-2026-110249
title: >-
  A malicious, compromised, or MITM-controlled Exchange server can return a
  single well-formed SOAP response containing an element with enough attributes
  to keep Thunderbird's main thread CPU-bound for seconds to hours
summary: >-
  A malicious, compromised, or MITM-controlled Exchange server can return a
  single well-formed SOAP response containing an element with enough attributes
  to keep Thunderbird's main thread CPU-bound for seconds to hours. This
  vulnerability …
severity: none
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T19:30:29.797'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110249'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2077826'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-109/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-110/'
    label: security@mozilla.org
tags:
  - nvd
ingestedAt: '2026-10-13T19:43:28.944Z'
---

## Overview

A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.

## Remediation

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