# CVE-2026-124474: MRBS before 1.12.3 Reflected XSS via error parameter of view_entry.php

Status: published. Published: 2026-11-08. Updated: 2026-11-13.

MRBS (Meeting Room Booking System) before 1.12.3 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject script via the error parameter of view_entry.php. Attackers can send crafted links to logged-in users to read CSRF tokens, modify or delete bookings, or perform administrative actions.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/meeting-room-booking-system/mrbs-code/commit/83b8253853359964f850208c28036b2bfa202466
- fix: mrbs-code (php): GitHub reports patched versions 1.12.3. Check the advisory for the affected release branch. (source: GitHub GHSA-5wqw-q7gh-j65v) — https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v

## Affected products and versions

- meeting-room-booking-system / mrbs-code (meeting-room-booking-system/mrbs-code): ≥ 0; < 1.12.3 (affected, semver); 1.12.3 (unaffected, semver). Source: CNA: VulnCheck
-  / mrbs-code (mrbs-code): <= 1.12.2 (affected, GitHub advisory range). Source: GitHub GHSA-5wqw-q7gh-j65v

## Severity and prioritization

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.21% as of 2026-11-12; percentile 11.41%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-79

## Exploit evidence

- exploit: https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v (ADP: CISA-ADP)

## References

- https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v (CNA: VulnCheck; vendor-advisory)

- https://github.com/meeting-room-booking-system/mrbs-code/commit/83b8253853359964f850208c28036b2bfa202466 (CNA: VulnCheck; patch)

- https://github.com/meeting-room-booking-system/mrbs-code/releases/tag/v1.12.3 (CNA: VulnCheck; release-notes)

- https://github.com/meeting-room-booking-system/mrbs-code/blob/38d51e05f4a0ab39820f3830ca5dcae5f34d8546/web/view_entry.php#L966-L969 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/mrbs-before-1.12.3-reflected-xss-via-error-parameter-of-view-entry-php (CNA: VulnCheck; third-party-advisory)

- https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v (ADP: CISA-ADP; exploit)

- https://github.com/meeting-room-booking-system/mrbs-code/blob/38d51e05f4a0ab39820f3830ca5dcae5f34d8546/web/view_entry.php#L966-L969 (disclosure@vulncheck.com)

- https://github.com/meeting-room-booking-system/mrbs-code/commit/83b8253853359964f850208c28036b2bfa202466 (disclosure@vulncheck.com)

- https://github.com/meeting-room-booking-system/mrbs-code/releases/tag/v1.12.3 (disclosure@vulncheck.com)

- https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/mrbs-before-1.12.3-reflected-xss-via-error-parameter-of-view-entry-php (disclosure@vulncheck.com)

- https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v (134c704f-9b21-4f2e-91b3-4a467353bcc0)

- https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v (GitHub Security Advisories; advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124474; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124474; retrieved 2026-11-13; source updated 2026-11-13

- GitHub Security Advisories: https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-5wqw-q7gh-j65v; retrieved 2026-11-13; source updated 2026-11-11

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-124474; retrieved 2026-11-13; source updated Not reported

Revision: 2074a32f6ccaa2427d86cc751cdd58cb5c6fe63c80f34c6316b8dc01de1a9e2e

Canonical: https://y2.dev/cve/CVE-2026-124474

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