Mastodon is a free, open-source social network server based on ActivityPub Mastodon which facilitates LDAP configuration for authentication. In versions 3.1.5 through 4.2.24, 4.3.0 through 4.3.11 and 4.4.0 through 4.4.3, Mastodon's rate-limiting system has a critical configuration error where the email-based throttle for confirmation emails incorrectly checks the password reset path instead of the confirmation path, effectively disabling per-email limits for confirmation requests. This allows attackers to bypass rate limits by rotating IP addresses and send unlimited confirmation emails to any email address, as only a weak IP-based throttle (25 requests per 5 minutes) remains active. The vulnerability enables denial-of-service attacks that can overwhelm mail queues and facilitate user harassment through confirmation email spam. This is fixed in versions 4.2.24, 4.3.11 and 4.4.3.
CVE-2025-54879
This medium-severity CVE scores 5.3 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 58% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 5.3(medium)
- EG Risk
- 55(Attend)EG Risk 55/100SSVC: Attend
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity53% × 45%Exploitation40% × 40%Automatability100% × 15%Action: Remediate soon — notable exploitation risk. - EPSS
- 41.9%
- KEV
- Not listed
Published
August 6, 2025
Last Modified
August 26, 2025
References (4)
- security-advisories@githubhttps://github.com/mastodon/mastodon/commit/e2592419d93fb41be03c2f3ff6a122fecb0e0952
- security-advisories@githubhttps://github.com/mastodon/mastodon/releases/tag/v4.4.3
- security-advisories@githubhttps://github.com/mastodon/mastodon/security/advisories/GHSA-84ch-6436-c7mg
- 134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/mastodon/mastodon/security/advisories/GHSA-84ch-6436-c7mg
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 11× in last 7d / 45× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 23:41 UTCOSV refresh
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- 2026-07-06 17:51 UTCOSV refresh
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- 2026-06-18 06:05 UTCOSV refresh
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- 2026-05-30 00:55 UTCEG score recompute
- 2026-05-29 13:44 UTCEPSS rescore
Related CVEs(same CWE)
Same CWE
10 shownCWE-770
- CVE-2018-20033EG 9.8CRITICAL
- CVE-2019-11479NVD 7.5EG 9.0EPSS 100%HIGH
- CVE-2019-11478NVD 5.3EG 9.0EPSS 100%MEDIUM
- CVE-2019-10088EG 8.8EPSS 91%HIGH
- CVE-2018-15462EG 8.6HIGH
- CVE-2018-15460EG 8.6HIGH
- CVE-2018-0137EG 8.6HIGH
- CVE-2008-5180NVD 5.3EG 7.9EPSS 99%MEDIUM
- CVE-2019-10094EG 7.8HIGH
- CVE-2018-16865EG 7.8HIGH
Frequently asked(5)
What is CVE-2025-54879?
When was CVE-2025-54879 disclosed?
Is CVE-2025-54879 actively exploited?
What is the CVSS score of CVE-2025-54879?
How do I remediate CVE-2025-54879?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2025-54879
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