CVE-2023-0430Network attack vector

Signature authenticity spoofing via skipped OCSP check

Published Jun 2, 2023 · Updated Jan 10, 2025

Improper certificate validation in Mozilla Thunderbird 68 through 102.7.0 allows remote attackers to spoof S/MIME signature validity. The S/MIME signature verifier omits the certificate's OCSP revocation-status check and consequently labels mail signed by a revoked certificate as valid. A recipient must open a crafted signed message; the flaw misrepresents signer trust but does not forge the cryptographic signature.

CVSS severity6.5
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Mozilla Thunderbird 68 through 102.7.0 allows remote attackers to spoof S/MIME signature validity. The S/MIME signature verifier omits the certificate's OCSP revocation-status check and consequently labels mail signed by a revoked certificate as valid. A recipient must open a crafted signed message; the flaw misrepresents signer trust but does not forge the cryptographic signature.

The record

CVE
CVE-2023-0430
Published
Jun 2, 2023
Updated
Jan 10, 2025
Vendor
Mozilla
Product
Thunderbird
Classifications
CWE-295, T1566
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 10, 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 <102.7.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Thunderbirdversion=unspecified <102.7.1

Published CVSS scores

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

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-295Improper Certificate Validation
T1566Phishing

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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