CVE-2026-48516

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 67% 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
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 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)
EG Risk
34(Track)
EG Risk 34/100SSVC: Track

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 computed
Severity75% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
33%
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.

Affected Packages

(1 across 1 ecosystem)
NuGet(1)
PackageVulnerable rangeFixed inDependents
MessagePack3.0.111-alpha ... 3.1.6 (15 versions)3.1.7—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 52× 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. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-24 22:13 UTCEG score recompute
  3. 2026-08-23 03:47 UTCEG score recompute
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-22 14:58 UTCEG score recompute
  6. 2026-08-21 23:49 UTCEPSS rescore
  7. 2026-08-21 09:30 UTCEG score recompute
  8. 2026-08-20 22:55 UTCEPSS rescore
  9. 2026-08-20 07:50 UTCEG score recompute
  10. 2026-08-19 17:04 UTCEPSS rescore
  11. 2026-08-19 04:51 UTCEG score recompute
  12. 2026-08-18 13:48 UTCEPSS rescore
  13. 2026-08-17 17:04 UTCEG score recompute
  14. 2026-08-17 13:47 UTCEPSS rescore
  15. 2026-08-17 03:29 UTCEG score recompute
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 14:40 UTCEG score recompute
  18. 2026-08-16 02:14 UTCEPSS rescore
  19. 2026-08-15 12:59 UTCEG score recompute
  20. 2026-08-15 01:30 UTCEPSS rescore
  21. 2026-08-13 22:26 UTCEG score recompute
  22. 2026-08-13 22:00 UTCEPSS rescore
  23. 2026-08-12 20:47 UTCEG score recompute
  24. 2026-08-12 13:51 UTCEPSS rescore
  25. 2026-08-11 19:09 UTCEG score recompute
Show 68 more
  1. 2026-08-11 06:14 UTCEG score recompute
  2. 2026-08-11 00:00 UTCEPSS rescore
  3. 2026-08-09 15:18 UTCEG score recompute
  4. 2026-08-09 13:46 UTCEPSS rescore
  5. 2026-08-09 02:30 UTCEG score recompute
  6. 2026-08-08 16:37 UTCEPSS rescore
  7. 2026-08-08 00:51 UTCEG score recompute
  8. 2026-08-06 23:14 UTCEG score recompute
  9. 2026-08-06 13:47 UTCEPSS rescore
  10. 2026-08-05 21:35 UTCEG score recompute
  11. 2026-08-05 19:17 UTCEPSS rescore
  12. 2026-08-04 15:56 UTCEG score recompute
  13. 2026-08-04 15:10 UTCEPSS rescore
  14. 2026-08-04 10:39 UTCEPSS rescore
  15. 2026-08-03 14:18 UTCEG score recompute
  16. 2026-08-03 10:36 UTCEPSS rescore
  17. 2026-08-02 11:48 UTCEG score recompute
  18. 2026-08-02 02:27 UTCEPSS rescore
  19. 2026-08-01 10:09 UTCEG score recompute
  20. 2026-08-01 04:16 UTCEPSS rescore
  21. 2026-07-30 19:23 UTCEG score recompute
  22. 2026-07-30 16:28 UTCEPSS rescore
  23. 2026-07-30 03:00 UTCEG score recompute
  24. 2026-07-30 01:30 UTCEPSS rescore
  25. 2026-07-29 01:21 UTCEG score recompute
  26. 2026-07-28 15:37 UTCEPSS rescore
  27. 2026-07-27 21:16 UTCEG score recompute
  28. 2026-07-26 15:58 UTCEG score recompute
  29. 2026-07-26 14:54 UTCEPSS rescore
  30. 2026-07-25 14:18 UTCEPSS rescore
  31. 2026-07-24 14:18 UTCEPSS rescore
  32. 2026-07-23 14:18 UTCEPSS rescore
  33. 2026-07-23 03:18 UTCEG score recompute
  34. 2026-07-22 14:08 UTCEPSS rescore
  35. 2026-07-21 15:25 UTCEPSS rescore
  36. 2026-07-20 17:08 UTCEPSS rescore
  37. 2026-07-19 14:31 UTCEPSS rescore
  38. 2026-07-19 02:29 UTCEPSS rescore
  39. 2026-07-18 10:04 UTCEPSS rescore
  40. 2026-07-16 17:03 UTCEPSS rescore
  41. 2026-07-15 16:57 UTCEPSS rescore
  42. 2026-07-15 02:00 UTCEPSS rescore
  43. 2026-07-13 22:30 UTCEPSS rescore
  44. 2026-07-13 06:13 UTCEPSS rescore
  45. 2026-07-12 05:46 UTCEPSS rescore
  46. 2026-07-11 08:27 UTCEPSS rescore
  47. 2026-07-09 19:10 UTCEPSS rescore
  48. 2026-07-08 15:16 UTCEPSS rescore
  49. 2026-07-07 13:46 UTCEPSS rescore
  50. 2026-07-06 16:27 UTCEPSS rescore
  51. 2026-07-06 02:23 UTCEPSS rescore
  52. 2026-07-05 02:30 UTCEPSS rescore
  53. 2026-07-04 06:31 UTCEPSS rescore
  54. 2026-07-01 15:07 UTCEPSS rescore
  55. 2026-06-29 14:06 UTCEPSS rescore
  56. 2026-06-29 14:06 UTCEPSS rescore
  57. 2026-06-28 14:07 UTCEPSS rescore
  58. 2026-06-28 04:56 UTCEPSS rescore
  59. 2026-06-28 04:56 UTCEPSS rescore
  60. 2026-06-27 03:08 UTCEPSS rescore
  61. 2026-06-25 13:49 UTCEPSS rescore
  62. 2026-06-24 14:05 UTCEPSS rescore
  63. 2026-06-23 22:03 UTCEG score recompute▲ 1.20
  64. 2026-06-23 21:33 UTCEPSS rescore
  65. 2026-06-23 21:33 UTCEPSS rescore
  66. 2026-06-23 17:33 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  67. 2026-06-23 00:02 UTCEG score recompute
  68. 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 0% probability of exploitation in the next 30 days, which ranks it in the top 66.6% of all scored CVEs.
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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