CVE-2026-117554

MEDIUMPre-NVD 4.34.3
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (21st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: a secondary CVSS source
Trending — 4 sources updated this week

Also known asEUVD-2026-110832 (ENISA EUVD) · GHSA-9v6c-vxr5-xp32 (GitHub Security Advisories)Source: ENISA EUVD

4.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 4.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Admidio before 5.0.17 contains an improper access control vulnerability that allows authenticated members to register event guests by submitting the additional_guests field when guests are disallowed. Attackers can set additional_guests to the remaining seat count in modules/events/events_function.php to exhaust event capacity and block other members from registering.

CVSS v3
4.3
EG Score
4.3MEDIUMlow confidence
EG Risk
19
EG Risk 19/100

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)
Severity43% × 45%
Impact severity (EG Severity): CVSS 4.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0% × 40%
No KEV listing, EG-KEV tier or EPSS when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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.
EPSS PROB
0.3%
EPSS %ILE
21st
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 (4.3): severity, escalated by confirmed exploitation. This CVE's 4.3 is its impact severity (EG Severity), not escalated.

EG Severity
4.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS. 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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

October 27, 2026

Last Modified

October 27, 2026

Advisory Details (7)

Auto-updated Oct 27, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
Web page

Admidio before 5.0.17 Event Guest Restriction Bypass via events_function.php | Advisories | VulnCheck

https://www.vulncheck.com/advisories/admidio-before-5.0.17-event-guest-restriction-bypass-via-events-function-php
Web page

admidio/modules/events/events_function.php at v5.0.16 · Admidio/admidio · GitHub

https://github.com/Admidio/admidio/blob/v5.0.16/modules/events/events_function.php#L446-L462
GitHub release Patch Available

5.0.17

Patch available: Admidio/admidio v5.0.17

https://github.com/Admidio/admidio/releases/tag/v5.0.17
GitHub commit Patch Available

commit 5b0ee3585d2a (Admidio/admidio)

Patch available: Admidio/admidio v5.0.17 (contains commit 5b0ee3585d2a)

https://github.com/Admidio/admidio/commit/5b0ee3585d2a69a6e85fee00b7b93f3ebc1e44d9
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Business logic flaw allows members to bypass guest restrictions and exhaust event capacity · Advisory · Admidio/admidio · GitHub

https://github.com/Admidio/admidio/security/advisories/GHSA-92g9-59rr-c3qg
Web page

GitHub - Admidio/admidio: Admidio is a free open source user management system for websites of organizations and groups. The system has a flexible role model so that it’s possible to reflect the structure and permissions of your organization. · GitHub

https://github.com/Admidio/admidio
Web page

Members could bypass guest restrictions and exhaust event capacity · Issue #2231 · Admidio/admidio · GitHub

https://github.com/Admidio/admidio/issues/2231

Vendor Advisories for CVE-2026-117554(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 / 9× 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.

  1. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  2. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  3. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  5. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-10-27 14:30 UTCEG score recompute
  7. 2026-10-27 14:01 UTCENISA EUVD ID recordedEUVD-2026-110832 · Source: ENISA EUVD
  8. 2026-10-27 13:37 UTCEG score recomputeFirst assessed: 4.3 MEDIUM
  9. 2026-10-27 13:34 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-117554?
CVE-2026-117554 is a medium-severity vulnerability; its CVE record was published on October 27, 2026. Admidio before 5.0.17 contains an improper access control vulnerability that allows authenticated members to register event guests by submitting the additional_guests field when guests are disallowed. Attackers can set additional_guests to the remaining seat count in…
When was CVE-2026-117554 made public?
CVE-2026-117554 was made public on October 8, 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 October 27, 2026. EchelonGraph's copy of the record carries a last-modified date of October 27, 2026; the record at its source may have been updated since.
Is CVE-2026-117554 actively exploited?
CVE-2026-117554 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-117554?
CVE-2026-117554 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-117554?
A fix for CVE-2026-117554 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-117554 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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