CVE-2026-49955

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 5.3 from GitHub Security Advisory (severity: MODERATE) published 2026-06-09. The CNA's CVSS baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: the CNA's CVSS, EPSS, GitHub Security Advisory

Also known asEUVD-2026-35494 (ENISA EUVD) · GHSA-wwx5-jq7h-rp7v (GitHub Security Advisories)Source: ENISA EUVD

5.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
5.3MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
48th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-07). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

June 9, 2026

Last Modified

November 8, 2026

Advisory Details (5)

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

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 pull request 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 pull request

[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 9× in last 7d / 34× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 248 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 148 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:53 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  4. 2026-11-10 16:44 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  5. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  6. 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  7. 2026-11-08 14:19 UTCEchelonGraph re-scored
  8. 2026-11-08 14:19 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub severity MODERATE · GitHub CVSS 5.3
  9. 2026-11-07 19:30 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub severity MODERATE · GitHub CVSS 5.3
  10. 2026-11-07 19:30 UTCEchelonGraph re-scored
  11. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  12. 2026-11-06 16:38 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  13. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  14. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  15. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  16. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  17. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  18. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  19. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  20. 2026-10-30 13:25 UTCOSV refresh
  21. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  22. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  23. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  24. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
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  1. 2026-10-25 14:22 UTCEchelonGraph re-scored
  2. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  3. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  4. 2026-10-22 22:59 UTCEchelonGraph re-scored
  5. 2026-10-22 22:59 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  6. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  7. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  8. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  9. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  10. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  11. 2026-10-18 03:33 UTCEchelonGraph re-scored
  12. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  13. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  14. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  15. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  16. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  17. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  18. 2026-10-12 15:59 UTCEchelonGraph re-scored
  19. 2026-10-11 19:42 UTCEchelonGraph re-scored
  20. 2026-10-11 16:57 UTCEchelonGraph re-scored
  21. 2026-10-11 14:21 UTCEchelonGraph re-scored
  22. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  23. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  24. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  25. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  26. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  27. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  28. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  29. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  30. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  31. 2026-10-03 09:39 UTCOSV refresh
  32. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  33. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  34. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  35. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  36. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  37. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  38. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  39. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  40. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  41. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  42. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-09-14 04:35 UTCEchelonGraph re-scored
  44. 2026-09-14 04:35 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  45. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  46. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  47. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  48. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  49. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  50. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  51. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  52. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  53. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  54. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  55. 2026-08-31 00:55 UTCEchelonGraph re-scored
  56. 2026-08-31 00:55 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  57. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  58. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  59. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  60. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  61. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  62. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  63. 2026-08-25 00:50 UTCEchelonGraph re-scored
  64. 2026-08-25 00:50 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  65. 2026-08-23 11:13 UTCEchelonGraph re-scored
  66. 2026-08-23 11:13 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  67. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  68. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  69. 2026-08-21 12:24 UTCEchelonGraph re-scored
  70. 2026-08-21 12:24 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  71. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  72. 2026-08-20 09:07 UTCEchelonGraph re-scored
  73. 2026-08-20 09:07 UTCGHSA enrichmentGHSA-wwx5-jq7h-rp7v · GitHub CVSS 5.3
  74. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  75. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.6% · 45th percentile

Frequently asked(5)

What is CVE-2026-49955?
CVE-2026-49955 is a medium-severity vulnerability; its CVE record was 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 made public?
CVE-2026-49955 was made public on June 5, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on June 9, 2026. EchelonGraph's copy of the record carries a last-modified date of November 8, 2026; the record at its source may have been updated since.
Is CVE-2026-49955 actively exploited?
CVE-2026-49955 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (48th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-49955?
CVE-2026-49955 has a CVSS base score of 5.3 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-49955?
A fix for CVE-2026-49955 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-49955 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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