CVE-2026-46349

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 94% 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).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to re-arrange a valid signed JSON-LD activity from a third-party actor to have it processed differently. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.

CVSS v3
5.3
EG Score
5.3(medium)
EPSS
5.8%
KEV
Not listed

Published

June 24, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 24, 2026
Patch available. Sources: github.
github Patch Available

LD-Signature Bypass via JSON-LD Named-Graph Restructuring · Advisory · mastodon/mastodon · GitHub

https://github.com/mastodon/mastodon/security/advisories/GHSA-chgx-jx3p-rf73

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 35× 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.

  1. 2026-07-12 05:46 UTCEPSS rescore
  2. 2026-07-12 05:34 UTCEG score recompute
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-11 03:35 UTCEG score recompute
  5. 2026-07-10 01:39 UTCEG score recompute
  6. 2026-07-09 19:10 UTCEPSS rescore
  7. 2026-07-08 23:42 UTCEG score recompute
  8. 2026-07-08 15:16 UTCEPSS rescore
  9. 2026-07-07 21:46 UTCEG score recompute
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-06 19:50 UTCEG score recompute
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-05 17:30 UTCEG score recompute
  14. 2026-07-05 02:30 UTCEPSS rescore
  15. 2026-07-04 15:34 UTCEG score recompute
  16. 2026-07-04 06:31 UTCEPSS rescore
  17. 2026-07-03 13:37 UTCEG score recompute
  18. 2026-07-02 11:42 UTCEG score recompute
  19. 2026-07-01 15:07 UTCEPSS rescore
  20. 2026-07-01 09:42 UTCEG score recompute
  21. 2026-06-30 23:22 UTCEPSS rescore
  22. 2026-06-30 07:46 UTCEG score recompute
  23. 2026-06-29 14:06 UTCEPSS rescore
  24. 2026-06-29 14:06 UTCEPSS rescore
  25. 2026-06-29 05:50 UTCEG score recompute
Show 10 more
  1. 2026-06-28 14:07 UTCEPSS rescore
  2. 2026-06-28 04:56 UTCEPSS rescore
  3. 2026-06-28 04:56 UTCEPSS rescore
  4. 2026-06-28 03:53 UTCEG score recompute
  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-27 01:57 UTCEG score recompute
  7. 2026-06-26 00:01 UTCEG score recompute
  8. 2026-06-25 13:49 UTCEPSS rescore
  9. 2026-06-24 22:03 UTCEG score recompute
  10. 2026-06-24 22:03 UTCNVD updatefirst tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-46349?
CVE-2026-46349 is a medium vulnerability published on June 24, 2026. Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to…
When was CVE-2026-46349 disclosed?
CVE-2026-46349 was first published in the National Vulnerability Database on June 24, 2026, with the most recent update on June 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-46349 actively exploited?
CVE-2026-46349 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-46349?
CVE-2026-46349 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-46349?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-46349, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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