CVE-2016-6271: The Bzrtp library (aka libbzrtp) 1.0.x before 1.0.4 allows man-in-the-middle attackers to conduct spoofing att

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HIGH 7.5REMOTEDOWNGRADE

CVE-2016-6271 is a high-severity flaw (CVSS 7.5) affecting bzrtp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Bzrtp library (aka libbzrtp) 1.0.x before 1.0.4 allows man-in-the-middle attackers to conduct spoofing attacks by leveraging a missing HVI check on DHPart2 packet reception.

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.2% (top 17%)
CISA exploited list	No
Weakness	CWE-254
Published	2017-01-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: bzrtp project

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

Am I affected?

Timeline

2017-01-18 22:59 UTCPublished CVE record published
2026-06-17 00:50 UTCUpdated Record last modified

bzrtp project bzrtp DOWNGRADE

Affected: 1.0.0 · 1.0.2 · 1.0.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison bzrtp sudo apt install bzrtp=<VERSION_BEFORE_1.0.0> sudo apt-mark hold bzrtp

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list bzrtp sudo dnf downgrade bzrtp-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add bzrtp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2016-6271?

bzrtp: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-6271 being exploited?

CVE-2016-6271 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-2016-6271 affect?

CVE-2016-6271 affects bzrtp. Severity is high (CVSS 7.5). The Bzrtp library (aka libbzrtp) 1.0.x before 1.0.4 allows man-in-the-middle attackers to conduct spoofing attacks by leveraging a missing HVI check on DHPart2 packet reception.

How urgent is CVE-2016-6271?

Priority 52/100. High severity; Remotely exploitable, no login, no user action

References

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