CVE-2026-58202

HIGHPre-NVD 8.38.3
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (14th 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: EPSS, a secondary CVSS source
Elevated

Also known asEUVD-2026-109154 (ENISA EUVD)Source: ENISA EUVD

8.3EG
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).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 8.3Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 2.0.0, the account-confirmation link in emails is built from the request Host header, with no allowlist. The unauthenticated POST /api/auth/resend-confirmation rotates a pending invitee's confirmation token and emails a link whose host comes from the request. An attacker who sends one resend-confirmation with Host: attacker.example and a pending invitee's email causes that invitee to receive a confirmation email whose only link points to the attacker. If the invitee clicks, the one-time confirmation token reaches the attacker, who then confirms the account on the real tenant domain and registers a passkey they control, taking over the account before the legitimate invitee ever uses it. All released versions through v1.1.0 are affected; no patched version exists yet. Reaching the app with a spoofed Host depends on the front proxy: the stock Caddy catch-all forwards it, while an operator who configures explicit per-tenant proxy blocks is not affected (see Details 4). The invite path builds links from the trusted tenant.domain (invite/+server.ts:204-210); the resend-confirmation path builds them from the request Host. This issue has been patched in version 2.0.0.

CVSS v3
8.3
EG Score
8.3HIGHmedium confidence
EG Risk
53
EG Risk 53/100

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)
Severity83% × 45%
Impact severity (EG Severity): CVSS 8.3 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.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (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
0.2%
EPSS %ILE
14th
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 (8.3): severity, escalated by confirmed exploitation. This CVE's 8.3 is its impact severity (EG Severity), not escalated.

EG Severity
8.3 HIGHCVSS-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
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 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 low, Track* at medium and Attend at high mission impact.

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

Exploitation public PoC (CISA Vulnrichment) · Automatable no (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)14 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 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

October 23, 2026

Last Modified

October 29, 2026

Advisory Details (3)

Auto-updated Oct 23, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit.
GitHub release Patch Available

v2.0.0

Patch available: open-reception/appointment-booking-software v2.0.0

https://github.com/open-reception/appointment-booking-software/releases/tag/v2.0.0
GitHub commit Patch Available

commit df5432776a1a (open-reception/appointment-booking-software)

Patch available: open-reception/appointment-booking-software v2.0.0 (contains commit df5432776a1a)

https://github.com/open-reception/appointment-booking-software/commit/df5432776a1a5b47c3a64d64e9d05dbe2b7a7819
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Confirmation-email links built from the request Host enable pending-account takeover via `POST /api/auth/resend-confirmation` · Advisory · open-reception/appointment-booking-software · GitHub

https://github.com/open-reception/appointment-booking-software/security/advisories/GHSA-w5g9-g2p4-2g4m

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 16× 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 16:35 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  4. 2026-10-29 19:26 UTCEG score recompute
  5. 2026-10-29 18:27 UTCEG score recompute
  6. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  7. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  8. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  9. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  10. 2026-10-26 14:08 UTCEG score recompute
  11. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  12. 2026-10-25 14:16 UTCEG score recompute
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  14. 2026-10-23 21:31 UTCEG score recompute
  15. 2026-10-23 20:35 UTCEG score recomputeFirst assessed: 8.3 HIGH
  16. 2026-10-23 20:34 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-58202?
CVE-2026-58202 is a high-severity vulnerability; its CVE record was published on October 23, 2026. OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 2.0.0, the account-confirmation link in emails is built from the request Host header, with no allowlist. The unauthenticated POST /api/auth/resend-confirmation rotates a…
When was the CVE record for CVE-2026-58202 published?
The CVE record for CVE-2026-58202 was published on October 23, 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 October 29, 2026; the record at its source may have been updated since.
Is CVE-2026-58202 actively exploited?
CVE-2026-58202 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-58202?
CVE-2026-58202 has a CVSS base score of 8.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-58202?
A fix for CVE-2026-58202 is available: update to the fixed version the vendor names in its advisory.

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