CVE-2026-96656: Plex Media Server External Control of File Name or Path Vulnerability

Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-10-23 as the remediation due date.

Patch available

What, why and how

Plex Media Server contains an external control of file name or path vulnerability which can allow an admin user to write arbitrary files that may be executed on load. This vulnerability can be chained with CVE-2026-96652, CVE-2026-96654, and CVE-2026-96655.

What

Why

The product allows user input to control or influence paths or file names that are used in filesystem operations.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

The product allows user input to control or influence paths or file names that are used in filesystem operations.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-10-20.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: a network path → External Control of File Name or Path → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Network
Privileges required: High: elevated access is required
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Not a CVSS 4.0 base metric
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-73 ↗
CWE-73: External Control of File Name or Path. The product allows user input to control or influence paths or file names that are used in filesystem operations.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkCWE-73CISA KEV

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-85370Known-exploited evidence recorded

Plex Media Server before 1.43.3.10861 allows an admin user to write arbitrary files that may be executed on load. The preference TranscoderH264Options is appended verbatim to x264's option string on every transcode. At startup, all .so files are run without signature, execute bit, or symbol checks.

Official EUVD record ↗

CSIRT Italia · Italian · plex-media-server-rilevato-sfruttamento-in-rete-delle-catena-di-attacco-plex2shellPlex Media Server: rilevato sfruttamento in rete delle catena di attacco Plex2Shell

È stato rilevato lo sfruttamento in rete di una catena di attacco, denominata Plex2Shell, che coinvolge le vulnerabilità CVE-2026-96652 , CVE-2026-96654 , CVE-2026-96655 e CVE-2026-96656 , presenti in Plex Media Server. Tali vulnerabilità, qualora sfruttate in sequenza, potrebbero consentire a un attaccante remoto non autenticato di effettuare richieste verso servizi interni tramite l’interfaccia di loopback, richiamare funzioni arbitrarie dei plugin, acquisire il token amministrativo e utilizzarlo per indurre il server a recuperare un contenuto multimediale opportunamente predisposto e scriverne i dati sotto forma di libreria condivisa nella directory dei codec. Il successivo caricamento della libreria potrebbe consentire l’esecuzione di codice arbitrario con i privilegi del servizio sui sistemi target. Di seguito la descrizione delle vulnerabilità: CVE-2026-96652 : di tipo “ Server-Side Request Forgery (SSRF) “ e con score CVSS v3.1 pari a 4.3, costituisce il primo anello della catena di sfruttamento e interessa l'endpoint /player/timeline , utilizzato dal protocollo Companion di Plex Media Server. Tale vulnerabilità è dovuta a meccanismi di controllo non adeguati riguardanti l’header X-Plex-Token e all’inserimento non sanificato del parametro protocol nell’URL di callback . Un attaccante remoto non autenticato, registrando un dispositivo con un token fittizio e indicando un URL opportunamente predisposto nel parametro protocol , potrebbe indurre il server a effettuare una richiesta POST dall'interfaccia di loopback verso un endpoint interno. CVE-2026-96654 : di tipo “ Improper Neutralization “ e con score CVSS v3.1 pari a 6.5, costituisce il secondo anello della catena e riguarda l’endpoint searchOne dell’API /system/agents/* , accessibile senza token da loopback. Tale vulnerabilità è dovuta a meccanismi di controllo non adeguati dell’identificatore dell’Agent e nell’URL interno utilizzato per richiamare le funzionalità dei plugin. Un attaccante, mediante richieste POST dall'interfaccia di loopback opportunamente predisposte e consentite dalla CVE-2026-96652, potrebbe controllare il percorso e i parametri delle successive richieste e richiamare funzioni arbitrarie dei plugin presenti. In particolare, potrebbe abusare della funzione GetResultFromNetwork dell’Agent TheTVDB e di un controllo incompleto sul prefisso http://127.0.0.1 per indurre il server a trasmettere a un sistema controllato il token amministrativo inserito nell’header X-Plex-Token . CVE-2026-96655 : di tipo “ Server-Side Request Forgery (SSRF) “ e con score CVSS v3.1 pari a 4.3, costituisce il terzo anello della catena e interessa l’endpoint /video/:/transcode/universal . Tale vulnerabilità è dovuta a controlli non adeguati sulle destinazioni indicate nel parametro path e sul percorso di scrittura specificato mediante l’opzione dump-yuv della preferenza TranscoderH264Options . Un attaccante in possesso del token amministrativo, acquisito mediante lo sfruttamento delle precedenti vulnerabilità, potrebbe indurre il server a recuperare un documento XML e un video opportunamente predisposti da un sistema sotto il proprio controllo. Configurando dump-yuv con un percorso nella directory Codecs , potrebbe quindi fare in modo che la transcodifica scriva i dati contenuti nei fotogrammi del video sotto forma di libreria condivisa .so in una posizione arbitraria. CVE-2026-96656 : di tipo “ External Control of File Name or Path ” e con score CVSS v3.1 pari a 7.2 (9.8 se concatenata alle precedenti vulnerabilità), costituisce l’ultimo anello della catena e interessa il caricamento delle librerie dalla directory Codecs . Tale vulnerabilità è dovuta al caricamento mediante dlopen dei file .so presenti nella directory dei codec senza adeguate verifiche della firma e dei permessi di esecuzione. Una successiva transcodifica determinerebbe il caricamento della libreria scritta mediante la CVE-2026-96655 e l’esecuzione automatica del relativo costruttore, consentendo a un attaccante l’esecuzione remota di codice con i privilegi del servizio Plex Media Server.

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2026-036173Plex, Inc.のPlex Media Serverにおけるファイル名やパス名の外部制御に関する脆弱性

Plex Media Serverのバージョン1.43.3.10861以前では、管理者ユーザーが任意のファイルを書き込み可能であり、そのファイルはロード時に実行される可能性があります。設定項目のTranscoderH264Optionsは、すべてのトランスコード時にx264のオプション文字列にそのまま追加されます。起動時には、すべての.soファイルが署名や実行権限、シンボルチェックなしで実行されます。

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-6999Plex 제품 보안 업데이트 권고

Plex Media Server에서 발생하는 External Control of File Name or Path 취약점(CVE-2026-96656) [1][6]

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-7001美 CISA 발표 주요 Exploit 정보공유(Update. 2026-10-20)

Plex Media Server Server-Side Request Forgery (SSRF) Vulnerability Plex Media Server Improper Neutralization of Encoded URI Schemes in a Web Page Vulnerability Plex Media Server External Control of File Name or Path Vulnerability

Official advisory ↗

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: Media Server: 0 < 1.43.3.10861
Fixed: Media Server: 1.43.3.10861
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 23 Sept 2026 · Last source change 21 Oct 2026, 03:56 UTC · CWE-73 · External Control of File Name or Path

CVE recordCVE.org · 5.2

CVSS sourceCNA

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-09-24

European sourceENISA EUVD · EUVD-2026-85370

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceCNA

NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

22 Oct 2026, 15:29 UTC
ENISA known-exploited stateENISA EUVD now records this CVE in its known-exploited dataset.
Before
not listed in ENISA EUVD known-exploited dataset
After
listed in ENISA EUVD known-exploited dataset (EUVD-2026-85370)
ENISA EUVD ↗
24 Sep 2026, 02:20 UTC
ENISA EUVD mappingEUVD-2026-85370 was added to the official ENISA EUVD mapping for this CVE.
Before
not recorded
After
{"euvdId":"EUVD-2026-85370"}
ENISA EUVD ↗
23 Sep 2026, 16:46 UTC
CISA KEV stateCISA KEV now confirms exploitation in the wild.
Before
not listed in CISA KEV
After
listed in CISA KEV since 2026-10-20
CISA KEV ↗
23 Sep 2026, 16:46 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2026-09-23CVE published

2026-10-20Added to CISA KEV

2026-10-21Fixed release or patch reference recorded

ENISA EUVD · EUVD-2026-85370↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

Plex Media Server External Control of File Name or Path Vulnerability

Published severity in operational context

Evidence used

Compensating controls

Verification

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2026-85370

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication