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CVE Record

CVE-2018-21031: Tautulli versions 2.1.38 and below allows remote attackers to bypass intended access control in Plex Media...

Tautulli versions 2.1.38 and below allows remote attackers to bypass intended access control in Plex Media Server because the X-Plex-Token is mishandled and can be retrieved from Tautulli. NOTE: Initially, this id was associated with Plex Media Server 1.18.2.2029-36236cc4c as the affected product and version. Further research indicated that Tautulli is the correct affected product.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Older Tautulli deployments could expose the Plex access token they are meant to protect. If an attacker can reach the affected Tautulli service, they may bypass intended access control for the associated Plex Media Server. The CVE record corrects earlier confusion: Tautulli, not Plex Media Server itself, is the affected product.

Executive priority

Prioritize if Tautulli is internet-facing or used with sensitive Plex libraries. The main business risk is unintended access through token leakage, not a confirmed mass-exploitation campaign based on the supplied evidence.

Technical view

CVE-2018-21031 affects Tautulli versions 2.1.38 and below. The issue is mishandling of the X-Plex-Token, allowing remote retrieval from Tautulli and access-control bypass against Plex Media Server. No CVSS, CWE, or vendor CPE data is provided in the supplied CVE bundle.

Likely exposure

Exposure is most likely in self-hosted Tautulli instances at version 2.1.38 or earlier, especially if reachable from the internet. Environments using Tautulli only on trusted internal networks have lower practical exposure but still need review.

Exploitation context

The supplied bundle references public discussion and an Exploit-DB document, but CISA KEV is false and no source in the bundle confirms active exploitation. Treat exploit knowledge as public, not necessarily observed in the wild.

Researcher notes

The record states the affected product was initially misattributed to Plex Media Server 1.18.2.2029-36236cc4c, then corrected to Tautulli. Researchers should avoid treating Plex Media Server alone as the vulnerable component without evidence of affected Tautulli exposure.

Mitigation direction

  • Identify all Tautulli instances and confirm their versions.
  • Upgrade Tautulli beyond affected versions where vendor guidance supports it.
  • Remove public internet exposure unless there is a documented business need.
  • Restrict Tautulli access with network controls and strong authentication.
  • Rotate Plex tokens if an affected Tautulli instance was exposed.

Validation and detection

  • Check whether any Tautulli instance is version 2.1.38 or earlier.
  • Confirm whether Tautulli is reachable from untrusted networks.
  • Review logs for unexpected access to Tautulli during exposure windows.
  • Verify Plex tokens were rotated after remediation if exposure existed.
  • Document whether the environment uses Tautulli at all.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2018-21031 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
5Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.