> CVE-2026-54047 [CRITICAL]

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PUBLISHED
2026-09-11 17:17
MODIFIED
2026-09-11 17:17
CVSS_SCORE V3
9.2
EPSS (Prob. Exploit)
0.30%
Top 78.0%
DATA SOURCES:
NVD đź”— 2026-09-11 CWE MITRE đź”— 2026-10-01 FIRST EPSS đź”— 2026-10-25 OSV đź”— 2026-09-14

> DESCRIPTION

Laci Synchroni is a decentralized mod and appearance sync server and plugin for Dalamud. Versions of the backend prior to 1.2.3 have an improper authentication vulnerability in the application's OAuth2 login flow. The application relies on client-side state by trusting the `UID` field inside the `Authentications` object of a user's local `config.json` file. By manually editing this local file on their PC prior to logging in, a user can supply an arbitrary UID. Because the server fails to validate that the authenticated OAuth2 identity matches the requested UID, an attacker can fully impersonate any target user and perform actions on their behalf. This issue has been resolved in version 1.2.3. The patch modifies `AuthorizeOauthAsync` inside the `SecretKeyAuthenticatorService` to strictly bind the lookup of the requested User ID (`requestedUid`) to the record of the successfully authenticated identity (`primaryUid`). The server will no longer load or return session tokens for a requested UID unless it matches the verified, authenticated database record. No known workarounds are available.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-287 CWE-349 CWE-602

> CWE DETAILED DESCRIPTIONS

CWE-287: Improper Authentication - When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. | CWE-349: Acceptance of Extraneous Untrusted Data With Trusted Data - The product, when processing trusted data, accepts any untrusted data that is also included with the trusted data, treating the untrusted data as if it were trusted. | CWE-602: Client-Side Enforcement of Server-Side Security - The product is composed of a server that relies on the client to implement a mechanism that is intended to protect the server.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Laci Synchroni Backend Vulnerable to Account Takeover / User Impersonation via Client-Side Configuration Manipulation

AFFECTED PACKAGES:
Unknown / Unknown
3 versions affected
ALIASES:
GHSA-gq4p-pxvg-6x9j

> HISTORIQUE DES MODIFICATIONS

Première apparition
11/09/2026 17:17
Source: NVD
đź“Š ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-287: Improper Authentication - When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. | CWE-349: Acceptance of Extraneous Unt...
Total des modifications: 1 Dernière mise à jour: 3 weeks ago

> REFERENCES

https://github.com/LaciSynchroni/server/commit/5bc3efd68b738328b8faeff089dd18a82...
https://github.com/LaciSynchroni/server/pull/28
https://github.com/LaciSynchroni/server/releases/tag/v1.2.3
https://github.com/LaciSynchroni/server/security/advisories/GHSA-gq4p-pxvg-6x9j
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