Answer in brief
CVE-2026-18503 records a Unknown severity vulnerability in Super-linear CPU usage for unbounded input to csv.Sniffer.sniff(). The current sources do not mark it as known exploited. The current feed maps Python Software Foundation/CPython (generic), 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-2026-18503 records a Unknown severity vulnerability in Super-linear CPU usage for unbounded input to csv.Sniffer.sniff(). The current sources do not mark it as known exploited. The current feed maps Python Software Foundation/CPython (generic), 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.
A CVSS score is not reported in the current record. 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), Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Python Software Foundation/CPythongeneric | >=0 <3.16.0 | 3.16.0 |
| Python Software Foundation/CPythongeneric | >=0 <3.13.15 || >=3.14.0 <3.14.7 || >=3.15.0a1 <3.15.0rc1 | 3.13.15, 3.14.7, 3.15.0rc1 |
Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().
Quoted source text, attributed separately from HOL analysis.
A CVSS score is not reported in the current record. 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), Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Python Software Foundation/CPythongeneric | >=0 <3.16.0 | 3.16.0 |
| Python Software Foundation/CPythongeneric | >=0 <3.13.15 || >=3.14.0 <3.14.7 || >=3.15.0a1 <3.15.0rc1 | 3.13.15, 3.14.7, 3.15.0rc1 |
Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().
Quoted source text, attributed separately from HOL analysis.