LiveActive security incident?Get immediate response
CVE Record

CVE-2021-23383: Prototype Pollution

The package handlebars before 4.7.7 are vulnerable to Prototype Pollution when selecting certain compiling options to compile templates coming from an untrusted source.

MediumCVSS 5.6Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-23383 affects Handlebars before 4.7.7. If an application compiles templates from untrusted sources with certain options enabled, an attacker may pollute JavaScript object prototypes. Business impact is generally moderate, but applications using user-supplied templates should treat it as higher priority.

Executive priority

Prioritize remediation in internet-facing or multi-tenant systems that process untrusted templates. Otherwise, handle through normal dependency patching, because sources indicate moderate severity and no confirmed active exploitation.

Technical view

The issue is prototype pollution in Handlebars template compilation. The CVE states it applies when certain compiling options are used with untrusted templates. CVSS 3.1 is 5.6 with network attack vector, high complexity, no privileges, no user interaction, and low confidentiality, integrity, and availability impact.

Likely exposure

Most exposure is in Node.js or Java WebJars applications that include vulnerable Handlebars versions and compile templates supplied by users, tenants, plugins, CMS content, or integrations.

Exploitation context

The bundle does not show CISA KEV listing or confirmed active exploitation. The CVSS temporal vector indicates proof-of-concept maturity, but practical exploitation depends on unsafe template compilation conditions.

Researcher notes

The key scoping detail is not just package presence, but whether untrusted templates are compiled with affected options. The source bundle does not provide full option names, exploit procedure, or downstream product version mapping beyond referenced advisories.

Mitigation direction

  • Upgrade Handlebars to 4.7.7 or later where applicable.
  • Update Java WebJars packages that embed vulnerable Handlebars versions.
  • Avoid compiling templates from untrusted sources unless vendor guidance explicitly supports it safely.
  • Review vendor advisories for affected downstream products, including NetApp guidance.

Validation and detection

  • Inventory npm, lockfiles, and WebJars dependencies for Handlebars versions before 4.7.7.
  • Identify code paths that compile templates from user-controlled or tenant-controlled input.
  • Check whether compile options match the risky scenario described by the CVE.
  • Run dependency scanning and confirm the upgraded package is actually deployed.
Prepared
Confidence
high
Sources
8

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.

cve · low confidence lookup

CVE-2021-23383 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
5.6 (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
7Source 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-2021-23383Attack 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.