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CVE-2026-46348

HIGHCVSS 8.7/10EPSS 0.34%

Last modified

CVE-2026-46348 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was lacking an IP address range that can be used to reach local IP addresses. EPSS estimates a 0.34% chance of exploitation in the next 30 days.

Description

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was lacking an IP address range that can be used to reach local IP addresses. An attacker can use an IP address in the affected range to make Mastodon perform HTTP requests against loopback interfaces, potentially allowing access to otherwise private resources and services. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.

Metrics

CVSS 4.0
8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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

EPSS Probability
0.34%

25.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-46348?
Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was lacking an IP address range that can be used to reach local IP addresses. An attacker can use an IP address in the affected range to make Mastodon perform HTTP requests against loopback interfaces, potentially allowing access to otherwise private resources and services. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.
How severe is CVE-2026-46348?
CVE-2026-46348 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.
How do I fix CVE-2026-46348?
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-2026-46348?

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

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Source: NVD / NIST