CVE-2026-6270 | fastify middie up to 9.3.1 interpretation conflict (GHSA-hrwm-hgmj-7p9c)

VDB-357927 · CVE-2026-6270 · GHSA-HRWM-HGMJ-7P9C FASTIFY MIDDIE UP TO 9.3.1 INTERPRETATION CONFLICT HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 8.0 $0-$5k 2.66+ Summaryinfo A vulnerability has been found in fastify middie up to 9.3.1 and classified as critical. This impacts an unknown function. Performing a manipulation results in interpretation conflict. This vulnerability is reported as CVE-2026-6270. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded. Detailsinfo A vulnerability was found in fastify middie up to 9.3.1. It has been classified as critical. This affects an unknown part. The manipulation with an unknown input leads to a interpretation conflict vulnerability. CWE is classifying the issue as CWE-436. Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is: @fastify/middie versions 9.3.1 and earlier do not register inherited middleware directly on child plugin engine instances. When a Fastify application registers authentication middleware in a parent scope and then registers child plugins with @fastify/middie, the child scope does not inherit the parent middleware. This allows unauthenticated requests to reach routes defined in child plugin scopes, bypassing authentication and authorization checks. Upgrade to @fastify/middie 9.3.2 to fix this issue. There are no workarounds. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-6270 since 04/14/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. Upgrading to version 9.3.2 eliminates this vulnerability. Productinfo Vendor fastify Name middie Version 9.3.0 9.3.1 CPE 2.3info 🔒 🔒 CPE 2.2info 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 8.2 VulDB Meta Temp Score: 8.0 VulDB Base Score: 7.3 VulDB Temp Score: 7.0 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 9.1 CNA Vector (openjs): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Interpretation conflict CWE: CWE-436 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: middie 9.3.2 Timelineinfo 04/14/2026 CVE reserved 04/16/2026 +2 days Advisory disclosed 04/16/2026 +0 days VulDB entry created 04/16/2026 +0 days VulDB entry last update Sourcesinfo Advisory: GHSA-hrwm-hgmj-7p9c Status: Confirmed CVE: CVE-2026-6270 (🔒) GCVE (CVE): GCVE-0-2026-6270 GCVE (VulDB): GCVE-100-357927 Entryinfo Created: 04/16/2026 16:47 Changes: 04/16/2026 16:47 (63) Complete: 🔍 Cache ID: 99:225:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸