Security readout for executives and security teams
Plain-English summary
CVE-2021-26505 concerns MrSwitch hello.js 1.18.6. The reported flaw is prototype pollution in hello.utils.extend, with the CVE description stating remote code execution is possible. The public bundle does not provide CVSS, confirmed affected CPEs, exploit evidence, or a named fix.
Executive priority
Prioritize confirmation of exposure before emergency action. If hello.js 1.18.6 is used in externally reachable code, escalate for remediation planning because the CVE alleges remote code execution, even though public severity and fix data are incomplete.
Technical view
The issue is reported as prototype pollution through hello.utils.extend in hello.js 1.18.6. Prototype pollution can corrupt inherited JavaScript object properties and, in some application contexts, lead to unsafe behavior. The provided sources do not describe preconditions, exploit chain details, patched versions, or reliable detection indicators.
Likely exposure
Exposure is most likely where applications include MrSwitch hello.js 1.18.6 and pass attacker-controlled data into paths using hello.utils.extend. The source bundle lists affected vendor/product as n/a, so confirm through dependency and bundled asset review rather than product assumptions.
Exploitation context
The source bundle does not show CISA KEV listing and provides no cited evidence of active exploitation. Treat exploitation status as unconfirmed. The CVE description says remote attackers can execute arbitrary code, but the bundle lacks supporting detail on reachability or required application conditions.
Researcher notes
The key evidence is sparse: one GitHub issue reference, no CVSS vector, no CWE, no CPEs, and no named patch in the bundle. Analysis should focus on dependency presence, reachability of hello.utils.extend, and whether any upstream guidance clarifies fixed versions.
Mitigation direction
- Inventory applications and bundles for MrSwitch hello.js 1.18.6.
- Check the GitHub issue and project guidance for confirmed remediation.
- Avoid passing untrusted objects into hello.utils.extend where feasible.
- Replace or upgrade only to a version confirmed safe by vendor guidance.
- Monitor CVE and project references for patch or advisory updates.
Validation and detection
- Search dependency manifests and built assets for hello.js 1.18.6.
- Identify application code paths invoking hello.utils.extend.
- Review whether attacker-controlled input can reach those merge paths.
- Check CVE and GitHub references for updated affected-version details.
- Record that KEV status is false in the provided bundle.
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.
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 lookupCVE-2021-26505 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/MrSwitch/hello.js/issues/634CVE reference
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.