Security readout for executives and security teams
Plain-English summary
CVE-2021-25943 affects the JavaScript package 101 versions 1.0.0 through 1.6.3. The flaw can let attacker-controlled input corrupt shared object behavior. Sources say this can cause denial of service and may lead to remote code execution, making affected production services a high-priority risk.
Executive priority
Prioritize this as critical for any production system using the affected package, especially exposed APIs. The business concern is service disruption and potential code execution. If the package is absent from deployed dependency inventories, urgency drops materially.
Technical view
The issue is prototype pollution, classified as CWE-1321, in the 101 package. The CVE record rates it CVSS 9.8 with network attack vector, low complexity, no privileges, and no user interaction. The cited code reference points to set.js, indicating risk around unsafe object property setting.
Likely exposure
Exposure is limited to applications or dependency trees using 101 versions 1.0.0 through 1.6.3. Risk is higher where application inputs can influence object keys or paths passed into vulnerable helper logic. The source bundle lists no CPEs, so asset discovery must rely on package inventories, lockfiles, and SBOMs.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. They do state denial of service impact and possible remote code execution. Treat internet-facing services and APIs using affected versions as urgent until package use and input reachability are validated.
Researcher notes
Evidence supports affected versions, CWE, severity, and impact category, but does not provide a confirmed fixed version, active exploitation evidence, or detailed product CPE mapping. Validate reachability carefully before declaring exploitable exposure.
Mitigation direction
- Inventory direct and transitive use of 101 versions 1.0.0 through 1.6.3.
- Check vendor or package maintainer guidance for a fixed version or replacement path.
- Remove or replace the dependency where no supported fix is available.
- Avoid passing untrusted object keys or paths into affected helper logic.
- Prioritize remediation for internet-facing services and security-sensitive backends.
Validation and detection
- Search package-lock, yarn.lock, pnpm-lock, SBOMs, and manifests for 101.
- Confirm whether deployed builds include affected versions, not only source repositories.
- Trace whether attacker-controlled input can reach 101 object-setting behavior.
- Review production dependency scans for CVE-2021-25943 findings.
- Document any compensating controls and remaining reachable uses.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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.
CWE-1321: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution 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 lookupCVE-2021-25943 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25943CVE reference · x_refsource_MISC
- https://github.com/tjmehta/101/blob/d87f63ce2a4cbdc476e8287abd78327c3144d646/set.js#L52CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.