CVEvulnerability

CVE-2026-22245

7.1 HIGH Published 2026-01-08 Modified 2026-06-17 Official page ↗
Status
Analyzed
Published
2026-01-08
Last modified
2026-06-17
Assigner
[email protected]
CVSS 4.0 ([email protected])
7.1 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weaknesses
CWE-918

Description

Mastodon is a free, open-source social network server based on ActivityPub. By nature, Mastodon performs a lot of outbound requests to user-provided domains. Mastodon, however, has some protection mechanism to disallow requests to local IP addresses (unless specified in `ALLOWED_PRIVATE_ADDRESSES`) to avoid the "confused deputy" problem. The list of disallowed IP address ranges was lacking some IP address ranges that can be used to reach local IP addresses. An attacker can use an IP address in the affected ranges to make Mastodon perform HTTP requests against loopback or local network hosts, potentially allowing access to otherwise private resources and services. This is fixed in Mastodon v4.5.4, v4.4.11, v4.3.17 and v4.2.29.

Affected configurations

• joinmastodon mastodon (< 4.2.29) • joinmastodon mastodon (>= 4.3.0 < 4.3.17) • joinmastodon mastodon (>= 4.4.0 < 4.4.11) • joinmastodon mastodon (>= 4.5.0 < 4.5.4)

Related

Weakness · CWE (1)

  • CWE-918 Server-Side Request Forgery weakness

References