CVE-2021-38165: Lynx through 2.8.9 mishandles the userinfo subcomponent of a URI, which allows remote attackers to discover cl

Q: How do I fix CVE-2021-38165?

lynx: upgrade to newer than 2.8.9; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-38165 being exploited?

CVE-2021-38165 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-38165 affect?

CVE-2021-38165 affects lynx, debian linux, fedora. Severity is medium (CVSS 5.3). 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.

Q: How urgent is CVE-2021-38165?

Priority 46/100. EPSS top 10%: very likely to be exploited; On your watchlist

This month

MEDIUM 5.3WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2021-38165 is a medium-severity flaw (CVSS 5.3) affecting lynx, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

EPSS top 10%: very likely to be exploited
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	3.9% (top 10%)
CISA exploited list	No
Weakness	CWE-522
Published	2021-08-07
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · fedoraproject · lynx project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-07 18:15 UTCPublished CVE record published
2026-06-17 04:01 UTCUpdated Record last modified

lynx project lynx UPGRADE

Affected: <= 2.8.9

Fixed in: newer than 2.8.9

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy lynx || rpm -q lynx || lynx --version

2. UPGRADE to newer than 2.8.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade lynx

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade lynx

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fedoraproject fedora MITIGATE

Affected: 33 · 34 · 35

Fixed in: no fixed release known

Safe to downgrade to: a release before 33

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-38165?

lynx: upgrade to newer than 2.8.9; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-38165 being exploited?

CVE-2021-38165 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-38165 affect?

CVE-2021-38165 affects lynx, debian linux, fedora. Severity is medium (CVSS 5.3). 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.

How urgent is CVE-2021-38165?

Priority 46/100. EPSS top 10%: very likely to be exploited; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

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CVE-2014-5002 HIGH 7.8 UPGRADE The lynx gem before 1.0.0 for Ruby places the configured password on command lines, which allows local users t
CVE-2012-5821 MEDIUM 5.9 MITIGATE MITIGATE Lynx does not verify that the server's certificate is signed by a trusted certification authority, which allow

References

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