CVE-2026-48516

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 86% 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, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, InterfaceLookupFormatter constructs an internal Dictionary> with the default equality comparer instead of the security-aware comparer supplied by options.Security.GetEqualityComparer(). This formatter omission allows hash-collision CPU denial of service against ILookup even when the application has opted into the untrusted-data security posture This vulnerability is fixed in 2.5.301 and 3.1.7.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
13.9%
KEV
Not listed

Published

June 22, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 23, 2026
Patch available. Sources: github.
github Patch Available

InterfaceLookupFormatter bypasses collision-resistant comparer settings · Advisory · MessagePack-CSharp/MessagePack-CSharp · GitHub

https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8

Vendor Advisories for CVE-2026-48516(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 44× 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. 2026-07-07 07:58 UTCEG score recompute
  2. 2026-07-06 18:47 UTCEG score recompute
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 05:22 UTCEG score recompute
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 16:32 UTCEG score recompute
  7. 2026-07-05 03:33 UTCEG score recompute
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 14:43 UTCEG score recompute
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-04 01:54 UTCEG score recompute
  12. 2026-07-03 13:03 UTCEG score recompute
  13. 2026-07-03 00:13 UTCEG score recompute
  14. 2026-07-02 11:23 UTCEG score recompute
  15. 2026-07-01 22:34 UTCEG score recompute
  16. 2026-07-01 15:07 UTCEPSS rescore
  17. 2026-07-01 09:43 UTCEG score recompute
  18. 2026-06-30 20:52 UTCEG score recompute
  19. 2026-06-30 08:03 UTCEG score recompute
  20. 2026-06-29 19:14 UTCEG score recompute
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-29 14:06 UTCEPSS rescore
  23. 2026-06-29 06:25 UTCEG score recompute
  24. 2026-06-28 17:32 UTCEG score recompute
  25. 2026-06-28 14:07 UTCEPSS rescore
Show 19 more
  1. 2026-06-28 04:56 UTCEPSS rescore
  2. 2026-06-28 04:56 UTCEPSS rescore
  3. 2026-06-28 04:41 UTCEG score recompute
  4. 2026-06-27 15:52 UTCEG score recompute
  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-27 03:04 UTCEG score recompute
  7. 2026-06-26 14:14 UTCEG score recompute
  8. 2026-06-26 01:20 UTCEG score recompute
  9. 2026-06-25 13:49 UTCEPSS rescore
  10. 2026-06-25 12:31 UTCEG score recompute
  11. 2026-06-24 23:41 UTCEG score recompute
  12. 2026-06-24 14:05 UTCEPSS rescore
  13. 2026-06-24 10:52 UTCEG score recompute
  14. 2026-06-23 22:03 UTCEG score recompute▲ 1.20
  15. 2026-06-23 21:33 UTCEPSS rescore
  16. 2026-06-23 21:33 UTCEPSS rescore
  17. 2026-06-23 17:33 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  18. 2026-06-23 00:02 UTCEG score recompute
  19. 2026-06-23 00:00 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-48516?
CVE-2026-48516 is a high vulnerability published on June 22, 2026. MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, InterfaceLookupFormatter<TKey,TElement> constructs an internal Dictionary<TKey, IGrouping<TKey,TElement>> with the default equality comparer instead of the security-aware comparer supplied by…
When was CVE-2026-48516 disclosed?
CVE-2026-48516 was first published in the National Vulnerability Database on June 22, 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-2026-48516 actively exploited?
CVE-2026-48516 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 13.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-48516?
CVE-2026-48516 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-48516?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-48516, 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.

Dependency Blast Radius

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