PT-2026-34728 · Mastodon · Mastodon

Evgeny Kopytin · CVE-2026-41259 · Published 2026-04-01 · Updated 2026-04-27

Positive Technologies (AI Summary)

CVSS v4.0

8.2

High

Base vector

AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions Mastodon versions prior to 4.5.9 Mastodon versions prior to 4.4.16 Mastodon versions prior to 4.3.22

Description Mastodon allows restricting new user sign-up based on e-mail domain names and performs basic validation on e-mail addresses, but it fails to restrict characters that some mailing servers interpret differently.

Recommendations Update to version 4.5.9 Update to version 4.4.16 Update to version 4.3.22

Exploit

Fix

Weakness Enumeration

CWE-841

Related Identifiers

BDU:2026-06821

BIT-MASTODON-2026-41259

CVE-2026-41259

GHSA-5R37-QPWQ-2JHH

Affected Products

Mastodon

References · 10

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41259.json · Exploit
• https://github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhh · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-06821 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-41259 · Security Note
• https://osv.dev/vulnerability/BIT-mastodon-2026-41259 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-41259 · Vendor Advisory
• https://github.com/mastodon/mastodon/releases/tag/v4.4.16 · Note
• https://github.com/mastodon/mastodon/releases/tag/v4.3.22 · Note
• https://github.com/mastodon/mastodon/releases/tag/v4.5.9 · Note
• https://twitter.com/CVEnew/status/2047428083188473929 · Twitter Post