CVE-2026-49955

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-06-09. a secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
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(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity53% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
44.5%
KEV
Not listed

Published

June 9, 2026

Last Modified

July 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 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. 2026-07-24 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:18 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-21 15:25 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 02:29 UTCEPSS rescore
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-16 17:03 UTCEPSS rescore
  12. 2026-07-16 13:18 UTCGHSA enrichment
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 10:07 UTCGHSA enrichment
  16. 2026-07-15 02:00 UTCEPSS rescore
  17. 2026-07-14 02:19 UTCGHSA enrichment
  18. 2026-07-13 22:30 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 22:57 UTCGHSA enrichment
  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-10 20:53 UTCGHSA enrichment
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-09 03:36 UTCGHSA enrichment
Show 65 more
  1. 2026-07-08 15:16 UTCEPSS rescore
  2. 2026-07-08 01:27 UTCGHSA enrichment
  3. 2026-07-07 13:46 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 02:51 UTCGHSA enrichment
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-05 02:30 UTCEPSS rescore
  8. 2026-07-05 00:46 UTCGHSA enrichment
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-03 22:10 UTCGHSA enrichment
  11. 2026-07-02 20:04 UTCGHSA enrichment
  12. 2026-07-01 17:59 UTCGHSA enrichment
  13. 2026-07-01 15:07 UTCEPSS rescore
  14. 2026-06-30 23:22 UTCEPSS rescore
  15. 2026-06-30 15:29 UTCGHSA enrichment
  16. 2026-06-29 14:06 UTCEPSS rescore
  17. 2026-06-29 14:06 UTCEPSS rescore
  18. 2026-06-29 11:12 UTCGHSA enrichment
  19. 2026-06-28 14:07 UTCEPSS rescore
  20. 2026-06-28 09:07 UTCGHSA enrichment
  21. 2026-06-28 04:56 UTCEPSS rescore
  22. 2026-06-28 04:56 UTCEPSS rescore
  23. 2026-06-27 07:03 UTCGHSA enrichment
  24. 2026-06-27 03:08 UTCEPSS rescore
  25. 2026-06-26 04:58 UTCGHSA enrichment
  26. 2026-06-25 13:49 UTCEPSS rescore
  27. 2026-06-25 02:53 UTCGHSA enrichment
  28. 2026-06-24 14:05 UTCEPSS rescore
  29. 2026-06-24 00:48 UTCGHSA enrichment
  30. 2026-06-23 21:33 UTCEPSS rescore
  31. 2026-06-23 21:33 UTCEPSS rescore
  32. 2026-06-22 22:23 UTCGHSA enrichment
  33. 2026-06-22 14:25 UTCEPSS rescore
  34. 2026-06-22 14:25 UTCEPSS rescore
  35. 2026-06-21 19:27 UTCGHSA enrichment
  36. 2026-06-21 14:56 UTCEPSS rescore
  37. 2026-06-21 14:56 UTCEPSS rescore
  38. 2026-06-21 01:59 UTCEPSS rescore
  39. 2026-06-21 01:59 UTCEPSS rescore
  40. 2026-06-20 14:26 UTCGHSA enrichment
  41. 2026-06-19 19:26 UTCEPSS rescore
  42. 2026-06-19 19:26 UTCEPSS rescore
  43. 2026-06-19 12:13 UTCGHSA enrichment
  44. 2026-06-18 17:52 UTCEPSS rescore
  45. 2026-06-18 17:52 UTCEPSS rescore
  46. 2026-06-18 09:39 UTCGHSA enrichment
  47. 2026-06-17 17:53 UTCEPSS rescore
  48. 2026-06-17 07:26 UTCGHSA enrichment
  49. 2026-06-16 17:53 UTCEPSS rescore
  50. 2026-06-16 04:50 UTCGHSA enrichment
  51. 2026-06-15 17:49 UTCEPSS rescore
  52. 2026-06-15 17:49 UTCEPSS rescore
  53. 2026-06-15 02:45 UTCGHSA enrichment
  54. 2026-06-14 23:18 UTCEPSS rescore
  55. 2026-06-14 00:41 UTCGHSA enrichment
  56. 2026-06-13 23:00 UTCEPSS rescore
  57. 2026-06-12 23:12 UTCEPSS rescore
  58. 2026-06-12 23:12 UTCEPSS rescore
  59. 2026-06-12 22:36 UTCGHSA enrichment
  60. 2026-06-11 20:31 UTCGHSA enrichment
  61. 2026-06-11 14:00 UTCEPSS rescore
  62. 2026-06-10 22:19 UTCEPSS rescore
  63. 2026-06-10 18:27 UTCGHSA enrichment
  64. 2026-06-09 16:23 UTCEG score recompute
  65. 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 July 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 44.5% 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 v3 base score of 5.3 (NVD).
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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-49955

Explore →

Is Your Infrastructure Affected by CVE-2026-49955?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs