CVE-2021-38165

Lynx through 2.8.9 mishandles the userinfo subcomponent of a URI, which allows remote attackers to discover cleartext credentials because they may appear in SNI data.

Published: 2021-08-07 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-38165 is rated Moderate Risk (52.9/100): CVSS Medium severity, with high exploitation likelihood (EPSS 4.46%, 90th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-38165

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 4.28% 4.46% +0.17%
2 2025-12-28 2.88% 4.28% +1.40%
3 2025-12-27 — 2.88% —

Full EPSS history (28 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38165

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 3.6 [email protected]
2.6 2.0 LOW
AV:N/AC:H/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 4.9 2.9 [email protected]

Weakness enumeration for CVE-2021-38165

OS Trackers for CVE-2021-38165

vendor priority summary link
alpine medium CVE-2021-38165: 1 source package rows (lynx); 8 state rows across 8 repos (3.11-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 1. https://security.alpinelinux.org/vuln/CVE-2021-38165
debian not yet assigned CVE-2021-38165 not yet assigned priority: Debian including 1 source packages (lynx), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-38165
redhat medium — https://access.redhat.com/security/cve/CVE-2021-38165
ubuntu medium CVE-2021-38165 medium priority: Ubuntu including 1 source packages (lynx), 14 status rows across 14 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 8, released 4, DNE 1, ignored 1. https://ubuntu.com/security/CVE-2021-38165

Affected software / configurations for CVE-2021-38165

Vendor Product Version Raw CPE
lynx_project lynx <= 2.8.9 cpe:2.3:a:lynx_project:lynx:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

References for CVE-2021-38165

URL Tags
http://www.openwall.com/lists/oss-security/2021/08/07/11 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/08/07/12 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/08/07/9 Mailing List Third Party Advisory
https://bugs.debian.org/991971 Issue Tracking Third Party Advisory
https://github.com/w3c/libwww/blob/f010b4cc58d32f34b162f0084fe093f7097a61f0/Library/src/HTParse.c#L118 Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00010.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7YMUHFJJWTZ6HBHTYXVDPNZINGGURHDW/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K6PZF7JNTFCOJ62HXZG4Q2NEHSZ6IO2V/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VKNK7GQBJBUBMJVNKVC7RTCYWUYMFJQW/
https://lynx.invisible-island.net/current/CHANGES.html Release Notes Third Party Advisory
https://www.debian.org/security/2021/dsa-4953 Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/08/07/1 Mailing List Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/08/07/11 Mailing List
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