CVE-2021-38165Public exploitNetwork attack vector

Cleartext credential disclosure via URI userinfo in SNI

Published Aug 7, 2021 · Updated Aug 4, 2024

Credential disclosure in Lynx 2.8.9 and earlier allows remote attackers to read cleartext credentials from TLS SNI data. HTLoadHTTP passes an ssl_host value containing the URI userinfo username and password to the TLS server-name indicator instead of stripping them. A user must open an HTTPS URL containing embedded credentials; the TLS ClientHello exposes them before certificate confirmation to the destination server and network observers.

CVSS severity5.3
Medium
EPSS probability4.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Credential disclosure in Lynx 2.8.9 and earlier allows remote attackers to read cleartext credentials from TLS SNI data. HTLoadHTTP passes an ssl_host value containing the URI userinfo username and password to the TLS server-name indicator instead of stripping them. A user must open an HTTPS URL containing embedded credentials; the TLS ClientHello exposes them before certificate confirmation to the destination server and network observers.

The record

CVE
CVE-2021-38165
Published
Aug 7, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-522, T1040
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.6NIST NVDAV:N/AC:H/Au:N/C:P/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/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 exploitPublished

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
T1040Network Sniffing

Public exploit references

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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