CVE-2023-42451

Name: CVE-2023-42451
Creator: NVD / NIST
Published: 2023-09-19T16:15:13.303+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.57%

Last modified Jun 17, 2026

CVE-2023-42451 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 3.5.14, 4.0.10, 4.1.8, and 4.2.0-rc2, under certain circumstances, attackers can exploit a flaw in domain name normalization to spoof domains they do not own. EPSS estimates a 0.57% chance of exploitation in the next 30 days.

Description

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 3.5.14, 4.0.10, 4.1.8, and 4.2.0-rc2, under certain circumstances, attackers can exploit a flaw in domain name normalization to spoof domains they do not own. Versions 3.5.14, 4.0.10, 4.1.8, and 4.2.0-rc2 contain a patch for this issue.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

0.57%

42.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-706

Affected Software

Vendor	Product	Versions	Update
Joinmastodon	Mastodon	< 3.5.14	—
Joinmastodon	Mastodon	>= 4.0.0, < 4.0.10	—
Joinmastodon	Mastodon	>= 4.1.0, < 4.1.8	—
Joinmastodon	Mastodon	4.2.0	Beta1

References

Timeline

Published: Sep 19, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-42451?

How severe is CVE-2023-42451?

CVE-2023-42451 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.57% probability of exploitation in the next 30 days.

How do I fix CVE-2023-42451?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-42451?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST