CVE-2026-49955

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH confidence

Score 5.3 from GitHub Security Advisory published 2026-06-09. the CNA's CVSS baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this week
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.3Exploit: NoneExposed: 0

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

Hermes WebUI before version 0.51.270 contains a resource exhaustion vulnerability that allows unauthenticated remote attackers to degrade service availability by repeatedly calling the passkey options endpoint without completing assertion. Attackers can send unlimited POST requests to the authentication endpoint, causing unbounded growth of the challenge store file and excessive CPU and disk I/O through repeated JSON file rewrites.

CVSS v3
5.3
EG Score
5.3(high)
EPSS
43.8%
KEV
Not listed

Published

June 9, 2026

Last Modified

June 23, 2026

Advisory Details (5)

Auto-updated Jun 16, 2026
Patch available. Sources: github_commit, github_pr, github_release.
generic

Hermes WebUI < 0.51.270 Resource Exhaustion via passkey/options | Advisories | VulnCheck

https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-passkey-options
github_release Patch Available

v0.51.270

Patch available: nesquena/hermes-webui v0.51.270

https://github.com/nesquena/hermes-webui/releases/tag/v0.51.270
github_pr Patch Available

Release v0.51.270 — Release IL (stage-u1 — un-hold batch: #3517 #3624 #3613)

Patch available: nesquena/hermes-webui v0.51.424 (PR #3674 merged 2026-06-05)

https://github.com/nesquena/hermes-webui/pull/3674
github_pr

[security] fix(auth): cap pending passkey challenges

Upstream fix in progress (PR #3624 · nesquena/hermes-webui, state=closed)

https://github.com/nesquena/hermes-webui/pull/3624
github_commit Patch Available

commit 58528a4d88b0 (nesquena/hermes-webui)

Patch available: nesquena/hermes-webui v0.51.424 (contains commit 58528a4d88b0)

https://github.com/nesquena/hermes-webui/commit/58528a4d88b0fa4f7b822e31d6051c669769bd3b

Vendor Advisories for CVE-2026-49955(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 / 86× 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. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 02:51 UTCEG score recompute
  3. 2026-07-06 02:51 UTCGHSA enrichment
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-05 00:46 UTCEG score recompute
  7. 2026-07-05 00:46 UTCGHSA enrichment
  8. 2026-07-04 06:31 UTCEPSS rescore
  9. 2026-07-03 22:10 UTCEG score recompute
  10. 2026-07-03 22:10 UTCGHSA enrichment
  11. 2026-07-02 20:04 UTCEG score recompute
  12. 2026-07-02 20:04 UTCGHSA enrichment
  13. 2026-07-01 17:59 UTCEG score recompute
  14. 2026-07-01 17:59 UTCGHSA enrichment
  15. 2026-07-01 15:07 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-30 15:29 UTCEG score recompute
  18. 2026-06-30 15:29 UTCGHSA enrichment
  19. 2026-06-29 14:06 UTCEPSS rescore
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 11:12 UTCEG score recompute
  22. 2026-06-29 11:12 UTCGHSA enrichment
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 09:08 UTCEG score recompute
  25. 2026-06-28 09:07 UTCGHSA enrichment
Show 61 more
  1. 2026-06-28 04:56 UTCEPSS rescore
  2. 2026-06-28 04:56 UTCEPSS rescore
  3. 2026-06-27 07:03 UTCEG score recompute
  4. 2026-06-27 07:03 UTCGHSA enrichment
  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-26 04:58 UTCEG score recompute
  7. 2026-06-26 04:58 UTCGHSA enrichment
  8. 2026-06-25 13:49 UTCEPSS rescore
  9. 2026-06-25 02:53 UTCEG score recompute
  10. 2026-06-25 02:53 UTCGHSA enrichment
  11. 2026-06-24 14:05 UTCEPSS rescore
  12. 2026-06-24 00:48 UTCEG score recompute
  13. 2026-06-24 00:48 UTCGHSA enrichment
  14. 2026-06-23 21:33 UTCEPSS rescore
  15. 2026-06-23 21:33 UTCEPSS rescore
  16. 2026-06-22 22:24 UTCEG score recompute
  17. 2026-06-22 22:23 UTCGHSA enrichment
  18. 2026-06-22 14:25 UTCEPSS rescore
  19. 2026-06-22 14:25 UTCEPSS rescore
  20. 2026-06-21 19:27 UTCEG score recompute
  21. 2026-06-21 19:27 UTCGHSA enrichment
  22. 2026-06-21 14:56 UTCEPSS rescore
  23. 2026-06-21 14:56 UTCEPSS rescore
  24. 2026-06-21 01:59 UTCEPSS rescore
  25. 2026-06-21 01:59 UTCEPSS rescore
  26. 2026-06-20 14:26 UTCEG score recompute
  27. 2026-06-20 14:26 UTCGHSA enrichment
  28. 2026-06-19 19:26 UTCEPSS rescore
  29. 2026-06-19 19:26 UTCEPSS rescore
  30. 2026-06-19 12:13 UTCEG score recompute
  31. 2026-06-19 12:13 UTCGHSA enrichment
  32. 2026-06-18 17:52 UTCEPSS rescore
  33. 2026-06-18 17:52 UTCEPSS rescore
  34. 2026-06-18 09:39 UTCEG score recompute
  35. 2026-06-18 09:39 UTCGHSA enrichment
  36. 2026-06-17 17:53 UTCEPSS rescore
  37. 2026-06-17 07:26 UTCEG score recompute
  38. 2026-06-17 07:26 UTCGHSA enrichment
  39. 2026-06-16 17:53 UTCEPSS rescore
  40. 2026-06-16 04:50 UTCEG score recompute
  41. 2026-06-16 04:50 UTCGHSA enrichment
  42. 2026-06-15 17:49 UTCEPSS rescore
  43. 2026-06-15 17:49 UTCEPSS rescore
  44. 2026-06-15 02:45 UTCEG score recompute
  45. 2026-06-15 02:45 UTCGHSA enrichment
  46. 2026-06-14 23:18 UTCEPSS rescore
  47. 2026-06-14 00:41 UTCEG score recompute
  48. 2026-06-14 00:41 UTCGHSA enrichment
  49. 2026-06-13 23:00 UTCEPSS rescore
  50. 2026-06-12 23:12 UTCEPSS rescore
  51. 2026-06-12 23:12 UTCEPSS rescore
  52. 2026-06-12 22:37 UTCEG score recompute
  53. 2026-06-12 22:36 UTCGHSA enrichment
  54. 2026-06-11 20:31 UTCEG score recompute
  55. 2026-06-11 20:31 UTCGHSA enrichment
  56. 2026-06-11 14:00 UTCEPSS rescore
  57. 2026-06-10 22:19 UTCEPSS rescore
  58. 2026-06-10 18:27 UTCEG score recompute
  59. 2026-06-10 18:27 UTCGHSA enrichment
  60. 2026-06-09 16:23 UTCEG score recompute
  61. 2026-06-09 16:22 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-49955?
CVE-2026-49955 is a medium vulnerability published on June 9, 2026. Hermes WebUI before version 0.51.270 contains a resource exhaustion vulnerability that allows unauthenticated remote attackers to degrade service availability by repeatedly calling the passkey options endpoint without completing assertion. Attackers can send unlimited POST requests to the…
When was CVE-2026-49955 disclosed?
CVE-2026-49955 was first published in the National Vulnerability Database on June 9, 2026, with the most recent update on June 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49955 actively exploited?
CVE-2026-49955 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 43.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49955?
CVE-2026-49955 has a CVSS v4.0 base score of 5.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-49955?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49955, 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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