CVE-2021-29416: An issue was discovered in PortSwigger Burp Suite before 2021.2

Q: How do I fix CVE-2021-29416?

burp suite: upgrade to 2021.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-29416 being exploited?

CVE-2021-29416 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-2021-29416 affect?

CVE-2021-29416 affects burp suite. Severity is medium (CVSS 6.5). An issue was discovered in PortSwigger Burp Suite before 2021.2. During viewing of a malicious request, it can be manipulated into issuing a request that does not respect its upstream proxy configuration. This could leak NetNTLM hashes on W

Q: How urgent is CVE-2021-29416?

Priority 45/100. Public exploit reference

This month

MEDIUM 6.5UPGRADE

CVE-2021-29416 is a medium-severity flaw (CVSS 6.5) affecting burp suite. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in PortSwigger Burp Suite before 2021.2. During viewing of a malicious request, it can be manipulated into issuing a request that does not respect its upstream proxy configuration. This could leak NetNTLM hashes on Windows systems that fail to block outbound SMB.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Published	2021-03-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: portswigger

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

Am I affected?

Timeline

2021-03-29 18:15 UTCPublished CVE record published
2026-06-17 03:47 UTCUpdated Record last modified

portswigger burp suite UPGRADE

Affected: < 2021.2

Fixed in: 2021.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy burp-suite || rpm -q burp-suite || burp-suite --version

2. UPGRADE to 2021.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade burp-suite

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade burp-suite

Note

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

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-2021-29416?

burp suite: upgrade to 2021.2. Exact commands for each OS are on this page.

Is CVE-2021-29416 being exploited?

CVE-2021-29416 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-2021-29416 affect?

CVE-2021-29416 affects burp suite. Severity is medium (CVSS 6.5). An issue was discovered in PortSwigger Burp Suite before 2021.2. During viewing of a malicious request, it can be manipulated into issuing a request that does not respect its upstream proxy configuration. This could leak NetNTLM hashes on W

How urgent is CVE-2021-29416?

Priority 45/100. Public exploit reference

Software pages

Windows vulnerabilities

Related CVEs

CVE-2022-35406 MEDIUM 4.3 UPGRADE A URL disclosure issue was discovered in Burp Suite before 2022.6
CVE-2021-44230 MEDIUM 6.5 UPGRADE PortSwigger Burp Suite Enterprise Edition before 2021.11 on Windows has weak file permissions for the embedded

References

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