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CVE Record

CVE-2021-23423: Directory Traversal

This affects the package bikeshed before 3.0.0. This can occur when an untrusted source file containing include, include-code or include-raw block is processed. The contents of arbitrary files could be disclosed in the HTML output.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Bikeshed before 3.0.0 could accidentally publish local file contents into generated HTML when it processed a malicious or untrusted source file. The issue is mainly a confidentiality risk for documentation or specification build workflows that accept outside input.

Executive priority

Prioritize remediation where Bikeshed handles external contributions or runs near credentials, source code, or internal files. This is not an internet-wide emergency, but it can expose sensitive data through routine publishing workflows.

Technical view

When Bikeshed before 3.0.0 processes untrusted source containing include, include-code, or include-raw blocks, directory traversal can cause arbitrary local files to be embedded in HTML output. CVSS 5.5 reflects local attack vector and required user interaction, with high confidentiality impact.

Likely exposure

Teams using Bikeshed in documentation or specification build pipelines are most exposed, especially where third-party contributions are rendered. Risk is lower when all source files are trusted and build environments contain no sensitive files.

Exploitation context

The supplied sources do not show active exploitation, and KEV is false. Exploitation requires a vulnerable Bikeshed workflow to process a malicious source file and expose the resulting HTML output.

Researcher notes

Evidence is limited to CVE metadata, Snyk advisory, and the referenced fix commit. No CWE is listed in the bundle. Do not assume broader product impact beyond Bikeshed before 3.0.0.

Mitigation direction

  • Upgrade Bikeshed to version 3.0.0 or later.
  • Avoid processing untrusted Bikeshed source files until upgraded.
  • Run documentation builds in restricted environments without sensitive local files.
  • Review vendor advisory and fix commit for deployment-specific guidance.

Validation and detection

  • Inventory projects and CI jobs that install or run Bikeshed.
  • Confirm installed Bikeshed versions are 3.0.0 or later.
  • Check whether builds process external or user-submitted source files.
  • Review generated HTML artifacts for unintended local file disclosure.
Prepared
Confidence
high
Sources
4

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-23423 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

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.

1CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N1.83.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2021-23423Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/abikeshedunspecifiedListed
Weakness

CWE details

No CWE listed

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