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CVE Record

CVE-2021-23369: Remote Code Execution (RCE)

The package handlebars before 4.7.7 are vulnerable to Remote Code Execution (RCE) when selecting certain compiling options to compile templates coming from an untrusted source.

MediumCVSS 5.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-23369 is a remote code execution issue in Handlebars before 4.7.7. Business risk depends on whether an application lets untrusted users supply templates and compiles them with risky options. It is rated medium, not listed in KEV, and the provided sources do not show active exploitation.

Executive priority

Treat as a targeted dependency remediation item, not a broad emergency. Raise priority for products that accept customer-provided templates or run template compilation in exposed services.

Technical view

Vulnerable Handlebars versions before 4.7.7 can allow code execution when compiling templates from an untrusted source with certain compile options. The CVSS 3.1 score is 5.6 with high attack complexity, network reachability, no privileges, and low confidentiality, integrity, and availability impact.

Likely exposure

Exposure is most likely in applications or services using Handlebars before 4.7.7 that compile user-controlled or third-party templates. Snyk references also cover WebJars packaging, so dependency inventories should include Java-packaged distributions where present.

Exploitation context

The source bundle marks KEV as false. The CVSS temporal vector indicates proof-of-concept maturity, but no cited source in the bundle confirms active exploitation. Practical risk appears conditional on untrusted template compilation and specific compiler options.

Researcher notes

The key condition is not just library presence; it is vulnerable Handlebars plus untrusted template compilation with certain options. Evidence is incomplete on exact option combinations in the provided bundle, so validation should focus on dependency version and data-flow review.

Mitigation direction

  • Upgrade Handlebars to 4.7.7 or later.
  • Update referenced WebJars-distributed Handlebars packages if present.
  • Avoid compiling templates from untrusted sources.
  • Review vendor advisories for product-specific remediation guidance.
  • Prioritize internet-facing services that accept template input.

Validation and detection

  • Inventory direct and transitive Handlebars dependencies.
  • Check package versions against the before-4.7.7 affected range.
  • Search code paths for runtime template compilation.
  • Confirm whether templates can be user-controlled or third-party supplied.
  • Review compile options used around untrusted templates.
Prepared
Confidence
high
Sources
9

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

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. 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-2021-23369 mapping review

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

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C

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
8Source 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
5.6CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C2.23.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.6Medium
CVSS 3.1 vector shape for CVE-2021-23369Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C

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/ahandlebarsunspecifiedListed
Weakness

CWE details

No CWE listed

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