CVE-2026-90898

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-14. A secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-77357 (ENISA EUVD) · GHSA-gqjq-cgxr-8c7c (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2.3%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Fixed versions, as the CVE record's CNA (JFrog) states them: "Upgrade Bifrost HTTP transport to 2.1.0 or later."

Bifrost registers MCP clients through its management API. A stdio client is a command plus args. Bifrost starts that program in the gateway the moment the client is added. No MCP handshake required.

The default is governance.auth_config.is_enabled=false. Auth off means every caller is a local admin. One unauthenticated POST /api/mcp/client is enough to run a program as the Bifrost process user (appuser on the official image).

 transports/v2.1.0 refuses an unauthenticated stdio registration with 403. transports/v2.0.0 still allows it.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
60
EG Risk 60/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation2.3% × 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 total (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
2.3%
EPSS %ILE
83rd
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
2.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). 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: 3 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 total (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)3 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 total (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

September 14, 2026

Last Modified

September 18, 2026

Advisory Details (3)

Auto-updated Oct 31, 2026
Patch available. Sources: github_commit, github_pr.
GitHub pull request Patch Available

mcp auth with ssrf checks

Patch available: maximhq/bifrost helm-chart-v2.1.46 (PR #6757 merged 2026-09-02)

https://github.com/maximhq/bifrost/pull/6757
GitHub commit Patch Available

commit 12e170352bd2 (maximhq/bifrost)

Patch available: maximhq/bifrost helm-chart-v2.1.46 (contains commit 12e170352bd2)

https://github.com/maximhq/bifrost/commit/12e170352bd25eab1ae9ba16611f1797d1fd8fdc
Web page

GitHub - maximhq/bifrost: Open-source, high-performance AI gateway that works as your LLM gateway, MCP gateway and agent gateway. One OpenAI-compatible API for 10,000+ models, with failover, load balancing, semantic caching, virtual keys, budgets and MCP Code Mode. Works with any SDK or agent and adds under 200µs of overhead at 5k RPS. · GitHub

https://github.com/maximhq/bifrost

Vendor Advisories for CVE-2026-90898(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 126× 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 it from the CNA feed. 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). Most recent first.

Showing the most recent 100 of 268 refreshes 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 168 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 17:58 UTCEG score recompute
  2. 2026-11-01 17:58 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-31 18:31 UTCEG score recompute
  4. 2026-10-31 18:30 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-31 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  6. 2026-10-30 18:57 UTCEG score recompute
  7. 2026-10-30 18:57 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-30 16:35 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  9. 2026-10-29 19:31 UTCEG score recompute
  10. 2026-10-29 19:31 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-29 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  12. 2026-10-28 20:05 UTCEG score recompute
  13. 2026-10-28 20:05 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-10-28 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  15. 2026-10-27 20:38 UTCEG score recompute
  16. 2026-10-27 20:38 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-27 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  18. 2026-10-26 21:12 UTCEG score recompute
  19. 2026-10-26 21:11 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-26 16:32 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  21. 2026-10-25 19:39 UTCEG score recompute
  22. 2026-10-25 19:39 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-10-25 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  24. 2026-10-25 13:51 UTCEG score recompute
  25. 2026-10-24 20:12 UTCEG score recompute
Show 75 more
  1. 2026-10-24 20:12 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  2. 2026-10-24 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  3. 2026-10-23 20:46 UTCEG score recompute
  4. 2026-10-23 20:46 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-23 16:32 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  6. 2026-10-22 21:18 UTCEG score recompute
  7. 2026-10-22 21:18 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-22 16:35 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  9. 2026-10-21 21:52 UTCEG score recompute
  10. 2026-10-21 21:52 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-21 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  12. 2026-10-20 21:44 UTCEG score recompute
  13. 2026-10-20 21:44 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-10-20 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  15. 2026-10-19 22:18 UTCEG score recompute
  16. 2026-10-19 22:18 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-19 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  18. 2026-10-18 21:08 UTCEG score recompute
  19. 2026-10-18 21:08 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-18 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  21. 2026-10-18 03:00 UTCEG score recompute
  22. 2026-10-17 21:41 UTCEG score recompute
  23. 2026-10-17 21:41 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-17 16:35 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  25. 2026-10-16 22:15 UTCEG score recompute
  26. 2026-10-16 22:15 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  27. 2026-10-16 16:45 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  28. 2026-10-15 18:52 UTCEG score recompute
  29. 2026-10-15 18:52 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  30. 2026-10-15 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  31. 2026-10-14 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  32. 2026-10-14 12:35 UTCEG score recompute
  33. 2026-10-14 12:35 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  34. 2026-10-14 12:30 UTCEG score recompute
  35. 2026-10-14 12:30 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  36. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  37. 2026-10-13 12:22 UTCEG score recompute
  38. 2026-10-13 12:22 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  40. 2026-10-12 14:46 UTCEG score recompute
  41. 2026-10-12 12:51 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-10-11 21:00 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  43. 2026-10-11 19:14 UTCEG score recompute
  44. 2026-10-11 16:30 UTCEG score recompute
  45. 2026-10-11 16:01 UTCEG score recompute
  46. 2026-10-11 16:01 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  47. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  48. 2026-10-11 13:45 UTCEG score recompute
  49. 2026-10-11 11:38 UTCEG score recompute
  50. 2026-10-11 11:38 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  51. 2026-10-11 06:11 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-10-10 23:07 UTCEG score recompute
  53. 2026-10-10 23:07 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  54. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  55. 2026-10-10 18:43 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  56. 2026-10-10 14:20 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-10-10 09:51 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-10-10 05:28 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  59. 2026-10-10 01:02 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-10-09 20:38 UTCEG score recompute
  61. 2026-10-09 20:38 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  63. 2026-10-09 16:14 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-10-09 07:49 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-10-09 03:23 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  66. 2026-10-08 23:00 UTCEG score recompute
  67. 2026-10-08 23:00 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  68. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  69. 2026-10-08 08:24 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  70. 2026-10-08 04:01 UTCEG score recompute
  71. 2026-10-08 04:01 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  73. 2026-10-07 23:36 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-10-07 19:14 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8
  75. 2026-10-07 12:55 UTCGHSA enrichmentGHSA-gqjq-cgxr-8c7c · GitHub severity CRITICAL · GitHub CVSS 9.8

Public detection templates

(1 reference)

A public Nuclei detection template is referenced for this CVE. A detection template checks whether a system is affected; it is not necessarily exploit code.

  • Nucleihttp/cves/2026/CVE-2026-90898.yaml
    Recorded Oct 13, 2026

    Bifrost < 2.1.0 - Unauthenticated MCP Stdio Command Execution

    Open source ↗

Frequently asked(5)

What is CVE-2026-90898?
CVE-2026-90898 is a critical-severity vulnerability; its CVE record was published on September 14, 2026. Bifrost registers MCP clients through its management API. A stdio client is a command plus args. Bifrost starts that program in the gateway the moment the client is added. No MCP handshake required. The default is governance.auth_config.is_enabled=false. Auth off means every caller is a local…
When was the CVE record for CVE-2026-90898 published?
The CVE record for CVE-2026-90898 was published on September 14, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 18, 2026; the record at its source may have been updated since.
Is CVE-2026-90898 actively exploited?
CVE-2026-90898 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.3% probability of exploitation in the next 30 days (83rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-90898?
CVE-2026-90898 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-90898?
A fix for CVE-2026-90898 is available: update to the fixed version the vendor names in its advisory. Fixed versions, as the CVE record's CNA (JFrog) states them: "Upgrade Bifrost HTTP transport to 2.1.0 or later." The vendor advisories EchelonGraph has for CVE-2026-90898 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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