CVE-2024-8394Network attack vector

Client crash via OTR verification use-after-free

Published Sep 6, 2024 · Updated Mar 19, 2025

Use-after-free in OTR chat verification in Mozilla Thunderbird before 128.2 allows remote attackers to crash the client during verification. Mozilla has not disclosed which OTR verification object is freed or which abort handler later accesses that released object. A user must participate in an OTR chat verification and abort it; exploitation interrupts the Thunderbird process without reported data disclosure or modification.

CVSS severity6.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in OTR chat verification in Mozilla Thunderbird before 128.2 allows remote attackers to crash the client during verification. Mozilla has not disclosed which OTR verification object is freed or which abort handler later accesses that released object. A user must participate in an OTR chat verification and abort it; exploitation interrupts the Thunderbird process without reported data disclosure or modification.

The record

CVE
CVE-2024-8394
Published
Sep 6, 2024
Updated
Mar 19, 2025
Vendor
Mozilla
Product
Thunderbird
Classifications
CWE-416, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 6, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 19, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <128.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Thunderbirdversion=unspecified <128.2

Published CVSS scores

6.5CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
6.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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