Answer in brief
CVE-2026-4519 records a Low severity (CVSS 3.3) vulnerability in webbrowser.open() allows leading dashes in URLs. The current sources do not mark it as known exploited. The current feed maps Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-4519 records a Low severity (CVSS 3.3) vulnerability in webbrowser.open() allows leading dashes in URLs. The current sources do not mark it as known exploited. The current feed maps Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 3.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Python Software Foundation/CPythongeneric | >=0 <3.13.13 || >=3.14.0 <3.14.4 || >=3.15.0a1 <3.15.0a8 | 3.13.13, 3.14.4, 3.15.0a8 |
Published upstream
Mar 20, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 15, 2026
The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().
Quoted source text, attributed separately from HOL analysis.
CVSS is 3.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Python Software Foundation/CPythongeneric | >=0 <3.13.13 || >=3.14.0 <3.14.4 || >=3.15.0a1 <3.15.0a8 | 3.13.13, 3.14.4, 3.15.0a8 |
Published upstream
Mar 20, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 15, 2026
The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().
Quoted source text, attributed separately from HOL analysis.