CVE-2026-8890

HIGHPre-NVD 8.28.2
EchelonGraph scoreMEDIUM confidence

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

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-05-26. The CNA's CVSS baseline 8.2; sources differ by 0.0.

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

Also known asEUVD-2026-31953 (ENISA EUVD) · GHSA-qggg-4j5m-mx55 (GitHub Security Advisories)Source: ENISA EUVD

8.2EG
EchelonGraph verdictPlan mitigationNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 8.2Exploit: No code on recordExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

code100x contains an authentication bypass vulnerability in the Mobile API that allows unauthenticated attackers to impersonate arbitrary users by supplying a crafted JSON payload in the 'g' HTTP header. The middleware in middleware.ts skips identity header generation when an Auth-Key header is present without validating its value, allowing attackers to inject a spoofed user identity header that the downstream route handler in the mobile courses endpoint accepts as trusted, granting unauthorized access to course data belonging to any enrolled user or administrator.

CVSS v3
8.2
EG Score
8.2HIGHmedium confidence
EG Risk
68
EG Risk 68/100

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)
Severity82% × 45%
Impact severity (EG Severity): CVSS 8.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
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 public PoC (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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
42nd
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 (8.2): severity, escalated by confirmed exploitation. This CVE's 8.2 is its impact severity (EG Severity), not escalated.

EG Severity
8.2 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% 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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.

Exploitation public PoC (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.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

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

May 26, 2026

Last Modified

November 8, 2026

Advisory Details (5)

Auto-updated Jun 3, 2026
Fix referenced — no release confirmed yet. Sources: github_pr.
GitHub pull request

fix: prevent user ID spoofing by stripping client-supplied 'g' header in withMobileAuth

Upstream fix in progress (PR #1927 · code100x/cms, state=open)

https://github.com/code100x/cms/pull/1927
Web page

bug: Mobile API - Pre -Authentication User ID Validation Bypass · Issue #1924 · code100x/cms · GitHub

https://github.com/code100x/cms/issues/1924
Web page

code100x Mobile API Authentication Bypass via Header Spoofing | Advisories | VulnCheck

https://www.vulncheck.com/advisories/code100x-mobile-api-authentication-bypass-via-header-spoofing
GitHub pull request

fix: prevent user ID spoofing by stripping client-supplied 'g' header in withMobileAuth

Upstream fix in progress (PR #1927 · code100x/cms, state=open)

https://github.com/code100x/cms/pull/1927/changes/90b489ee7c63c301107d6374d4b3f2b8e4060fe5
GitHub pull request

fix: prevent user ID spoofing by stripping client-supplied 'g' header in withMobileAuth

Upstream fix in progress (PR #1927 · code100x/cms, state=open)

https://github.com/code100x/cms/pull/1927/changes/88c6c5e94e23da101235c4c7e9c7591ac1016549

Vendor Advisories for CVE-2026-8890(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 8× 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 287 rows on record for this CVE, as 99 entries (1 repeat merged).

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. 1 repeat row among the latest 100 is merged into the row it repeats. The 187 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:58 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  2. 2026-11-12 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  3. 2026-11-11 16:41 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
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  6. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-11-08 14:17 UTCEchelonGraph re-scored
  8. 2026-11-08 14:17 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  9. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-11-05 16:39 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-11-04 16:37 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-11-04 15:46 UTCEchelonGraph re-scored
  14. 2026-11-04 15:46 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  15. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  17. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
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  21. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-10-28 07:36 UTCEchelonGraph re-scored
  23. 2026-10-28 07:36 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  24. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  25. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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  1. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  2. 2026-10-25 13:53 UTCEchelonGraph re-scored
  3. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  4. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  5. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  7. 2026-10-20 17:51 UTCEchelonGraph re-scored
  8. 2026-10-20 17:51 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  9. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  10. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  11. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  12. 2026-10-18 03:03 UTCEchelonGraph re-scored
  13. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  14. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  15. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  17. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  18. 2026-10-13 05:00 UTCEchelonGraph re-scored
  19. 2026-10-13 05:00 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  20. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  21. 2026-10-12 14:49 UTCEchelonGraph re-scored
  22. 2026-10-11 19:15 UTCEchelonGraph re-scored
  23. 2026-10-11 16:32 UTCEchelonGraph re-scored
  24. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  25. 2026-10-11 13:48 UTCEchelonGraph re-scored
  26. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 45th percentile
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  34. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.6% · 45th percentile
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  37. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 45th percentile
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  39. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  40. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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  45. 2026-09-16 14:09 UTCEPSS rescoreEPSS 0.5% · 40th percentile
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  47. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  48. 2026-09-14 09:39 UTCEchelonGraph re-scored
  49. 2026-09-14 09:39 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  50. 2026-09-13 16:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
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  67. 2026-08-24 14:18 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  68. 2026-08-23 15:56 UTCEchelonGraph re-scored
  69. 2026-08-23 15:56 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  70. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  71. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  72. 2026-08-21 21:21 UTCEchelonGraph re-scored
  73. 2026-08-21 21:21 UTCGHSA enrichmentGHSA-qggg-4j5m-mx55 · GitHub severity HIGH · GitHub CVSS 8.2
  74. 2026-08-20 22:56 UTCEPSS rescoreEPSS 0.5% · 40th percentile

Frequently asked(5)

What is CVE-2026-8890?
CVE-2026-8890 is a high-severity vulnerability; its CVE record was published on May 26, 2026. code100x contains an authentication bypass vulnerability in the Mobile API that allows unauthenticated attackers to impersonate arbitrary users by supplying a crafted JSON payload in the 'g' HTTP header. The middleware in middleware.ts skips identity header generation when an Auth-Key header is…
When was CVE-2026-8890 made public?
CVE-2026-8890 was made public on May 26, 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 May 26, 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-2026-8890 actively exploited?
CVE-2026-8890 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (42nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-8890?
CVE-2026-8890 has a CVSS base score of 8.2 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-8890?
A fix for CVE-2026-8890 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2026-8890 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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