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CVE-2019-16366· NVD / CVE Program· CNA mitre

In XS 9.0.0 in Moddable SDK OS180329, there is a heap-based buffer overflow in fxBeginHost in xsAPI.c when called from fxRunDefine in xsRun.

In XS 9.0.0 in Moddable SDK OS180329, there is a heap-based buffer overflow in fxBeginHost in xsAPI.c when called from fxRunDefine in xsRun.c, as demonstrated by crafted JavaScript code to xst.

CriticalCVSS 9.8 · v3.1—No exploit No fix recorded
Published
Sep 16, 2019
Updated
Jun 16, 2026
EPSS
1.4% · 70th percentile
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Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.4%

Affected systems

VendorProduct
moddablemoddable
moddablexs

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • moddable moddableos180329
  • moddable xs9.0.0

Same product

moddable: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-25462Heap buffer overflow in the fxCheckArrowFunction function at moddable/xs/sources/xsSyntaxical.c:3562 in Moddable SDK before OS200903.
    40Plan
  • CVE-2021-29329OpenSource Moddable v10.5.0 was discovered to contain a stack overflow in the fxBinaryExpressionNodeDistribute function at /moddable/xs/sour
    31Monitor
  • CVE-2021-29327OpenSource Moddable v10.5.0 was discovered to contain a heap buffer overflow in the fx_ArrayBuffer function at /moddable/xs/sources/xsDataVi
    31Monitor
  • CVE-2021-29326OpenSource Moddable v10.5.0 was discovered to contain a heap buffer overflow in the fxIDToString function at /moddable/xs/sources/xsSymbol.c
    31Monitor
  • CVE-2021-29325OpenSource Moddable v10.5.0 was discovered to contain a heap buffer overflow in the fx_String_prototype_repeat function at /moddable/xs/sour
    31Monitor
  • CVE-2021-29324OpenSource Moddable v10.5.0 was discovered to contain a stack overflow via the component /moddable/xs/sources/xsScript.c.
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

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