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No exploitation reported

CVE-2026-110249

No exploitation reported by the sources we read.

  • Published2026-10-13
  • WeaknessCWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-10-1319:18CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-110249?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-110249?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-110249 Red Hat Product Security10 known affected

    thunderbird: Denial-of-service in the Exchange email component

    thunderbird as a component of Red Hat Enterprise Linux 10 · thunderbird.src as a component of Red Hat Enterprise Linux 10 · thunderbird as a component of Red Hat Enterprise Linux 6 · +7 more

Full record on NVD

Fix

  1. No fix available, says the vendor Red Hat Product Security CVE-2026-110249 · 2 productsFix deferred
  2. No fix available, says the vendor Red Hat Product Security CVE-2026-110249 · 4 productsAffected
  3. No fix planned, says the vendor Red Hat Product Security CVE-2026-110249 · 4 productsOut of support scope

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Published
2026-10-13
Last Modified
2026-10-20
NVD status
Awaiting Analysis

Frequently asked questions

What is CVE-2026-110249?

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.

Is CVE-2026-110249 actively exploited?

Active exploitation of CVE-2026-110249 has not been confirmed. Its EPSS score was 0.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-110249?

CVE-2026-110249 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.

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