CVE-2024-40464Network attack vector

SMTP interception via disabled TLS certificate verification

Published Jul 31, 2024 · Updated Aug 6, 2024

Improper certificate validation in Beego through 2.2.0 allows man-in-the-middle attackers to intercept SMTP log email over STARTTLS. The sendMail function in core/logs/smtp.go hard-codes tls.Config.InsecureSkipVerify to true, so STARTTLS accepts an untrusted SMTP certificate. Exploitation requires the SMTP log adapter and a network position between the application and SMTP server; the consequence is exposure or modification of log email and, when authentication is configured, SMTP credentials.

CVSS severity8.7
High
EPSS probability0.57%
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 Beego through 2.2.0 allows man-in-the-middle attackers to intercept SMTP log email over STARTTLS. The sendMail function in core/logs/smtp.go hard-codes tls.Config.InsecureSkipVerify to true, so STARTTLS accepts an untrusted SMTP certificate. Exploitation requires the SMTP log adapter and a network position between the application and SMTP server; the consequence is exposure or modification of log email and, when authentication is configured, SMTP credentials.

The record

CVE
CVE-2024-40464
Published
Jul 31, 2024
Updated
Aug 6, 2024
Vendor
Beego
Product
Beego
Classifications
CWE-599, CWE-295, T1557
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 31, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 2024Record 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=0 <=2.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Beego · Beegoversion=0 <=2.2.0

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-599Missing Validation of OpenSSL Certificate
CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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