Medium Access control

CVE-2026-48076 — OpenReception's bootstrap booking flow allows unauthenticated booking on isPublic=false channels

OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. The new-client booking flow in versions 1.0.1 and prior consists of three calls: `bootstrap-challenge` (returns a 16-bit PoW challenge with `difficulty=4` leading hex zeroes), `bootstrap-verify` (validates the PoW and issues a Bearer booking access token), and `create-new-client` (consumes the token and creates the tunnel and first appointment). The token correctly binds to `tenantId`, `tunnelId`, `clientPublicKey`, and `emailHash`, but never to `channelId`. The `bootstrap-challenge` request schema does not even accept a `channelId`, and the issued token's payload contains no channel information. Independently, the service function `createNewClientWithAppointment` checks only `channel.archived = false`. The `channel.isPublic` check that protects `addAppointmentToTunnel` is missing in the new-client path. The combination means: an attacker completes the bootstrap flow normally (16-bit PoW, completes in well under one second on commodity hardware, no rate limiting beyond the throttle store), receives a valid booking access token, and then submits the `create-new-client` payload with `channelId` pointing to a private (`isPublic = false`) channel. The booking lands as `CONFIRMED` if the target channel has `requiresConfirmation = false` (the default), otherwise as `NEW`. The patient-facing UI does not list private channels in its picker (`/api/public/channels` correctly filters `isPublic = true`), so the channel ID must be obtained out of band. The companion finding V-10 (schedule endpoint discloses private channels) provides exactly that: a single unauthenticated GET reveals every private channel ID for any tenant. V-10 plus V-11 together make private channels fully reachable to anonymous attackers. As of time of publication, no known patched versions are available.

Published Aug 6, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3
CISA SSVC: exploitation "poc"+5
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Open-reception

Appointment-booking-software

CVSS base

6.5

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Open-reception Appointment-booking-software).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Open-reception	Appointment-booking-software	version <= 1.0.1	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
6.5	CVSS 3.1	Medium	3.9	2.5	security-advisories@github.com via NIST National Vulnerability Database
6.5	CVSS 3.1	Medium	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-863 · Incorrect Authorization

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Audit administrative actions and access to resources outside each user’s normal pattern.

web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · open-reception/appointment-booking-software
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 6.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 6, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

github.com/open-reception/appointment-booking-software/security/advisories/GHSA-
x_refsource_CONFIRM, NIST National Vulnerability Database

Elsewhere on this site

Open-reception
every CVE for this vendor

Access control
same class

CWE-863
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-48086 OpenReception: Tenant admin self-promotes to GLOBAL_ADMIN Aug 6, 2026
Medium CVE-2026-48083 OpenReception: Unauthenticated POST /api/log accepts arbitrary content with CRLF injection and no size or rate limits Aug 6, 2026
High CVE-2026-48084 OpenReception doesn't rate limit passphrase login attempts Aug 6, 2026
Critical CVE-2026-48085 OpenReception has unauthenticated GLOBAL_ADMIN account creation post-bootstrap Aug 6, 2026
Critical CVE-2026-48087 OpenReception: WebAuthn passkey injection allows account takeover Aug 6, 2026
Critical CVE-2026-48088 OpenReception vulnerable to unauthenticated staff crypto poisoning that breaks E2E recipient directory Aug 6, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-48076 is "OpenReception's bootstrap booking flow allows unauthenticated booking on isPublic=false channels", rated Medium. It affects Appointment-booking-software (Open-reception); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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