Mastodon 4.1.x before 4.1.17 and 4.2.x before 4.2.9 allows a bypass of rate limiting via a crafted HTTP request header.
Conclusion & alert: CVE-2023-49952 is rated Moderate Risk (42.6/100): CVSS High severity, with low exploitation likelihood (EPSS 0.17%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-11-21 | 0.91% | 0.17% | -0.75% |
| 2 | 2025-11-18 | 0.17% | 0.91% | +0.75% |
| 3 | 2025-09-14 | — | 0.17% | — |
Full EPSS history (12 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| joinmastodon | mastodon | >= 4.1.0, < 4.1.17 | cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:* |
| joinmastodon | mastodon | >= 4.2.0, < 4.2.9 | cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://github.com/mastodon/mastodon/security | Product |
| https://github.com/mastodon/mastodon/security/advisories/GHSA-c2r5-cfqr-c553 | Vendor Advisory |