CVE-2023-33983: The Introduction Client in Briar through 1.5.3 does not implement out-of-band verification for the public keys

Q: How do I fix CVE-2023-33983?

briar: upgrade to newer than 1.5.3. Exact commands for each OS are on this page.

Q: Is CVE-2023-33983 being exploited?

CVE-2023-33983 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-2023-33983 affect?

CVE-2023-33983 affects briar. Severity is high (CVSS 7.4). The Introduction Client in Briar through 1.5.3 does not implement out-of-band verification for the public keys of introducees. An introducer can launch man-in-the-middle attacks against later private communication between two introduced par

Q: How urgent is CVE-2023-33983?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.4REMOTEUPGRADE

CVE-2023-33983 is a high-severity flaw (CVSS 7.4) affecting briar. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Introduction Client in Briar through 1.5.3 does not implement out-of-band verification for the public keys of introducees. An introducer can launch man-in-the-middle attacks against later private communication between two introduced parties.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.4 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-862
Published	2023-05-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: briarproject

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

Am I affected?

Timeline

2023-05-24 18:15 UTCPublished CVE record published
2026-06-17 06:02 UTCUpdated Record last modified

briarproject briar UPGRADE

Affected: <= 1.5.3

Fixed in: newer than 1.5.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.5.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade briar

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-2023-33983?

briar: upgrade to newer than 1.5.3. Exact commands for each OS are on this page.

Is CVE-2023-33983 being exploited?

CVE-2023-33983 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-2023-33983 affect?

CVE-2023-33983 affects briar. Severity is high (CVSS 7.4). The Introduction Client in Briar through 1.5.3 does not implement out-of-band verification for the public keys of introducees. An introducer can launch man-in-the-middle attacks against later private communication between two introduced par

How urgent is CVE-2023-33983?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

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References

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