Python up to 3.15.x csv csv.py csv.Sniffer.sniff csv injection

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.1$0-$5k1.08+

Summaryinfo

A vulnerability identified as problematic has been detected in Python up to 3.15.x. Affected by this vulnerability is the function csv.Sniffer.sniff of the file csv.py of the component csv. Performing a manipulation results in csv injection. This vulnerability is known as CVE-2026-18503. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability classified as problematic has been found in Python up to 3.15.x. This affects the function csv.Sniffer.sniff of the file csv.py of the component csv. The manipulation with an unknown input leads to a csv injection vulnerability. CWE is classifying the issue as CWE-1236. The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product. This is going to have an impact on availability. The summary by CVE is:

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().

The advisory is shared at mail.python.org. This vulnerability is uniquely identified as CVE-2026-18503 since 07/31/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available.

Upgrading to version 3.16.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Csv injection
CWE: CWE-1236 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Python 3.16.0

Timelineinfo

07/31/2026 CVE reserved
08/10/2026 +10 days Advisory disclosed
08/10/2026 +0 days VulDB entry created
08/10/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mail.python.org
Status: Confirmed

CVE: CVE-2026-18503 (🔒)
GCVE (CVE): GCVE-0-2026-18503
GCVE (VulDB): GCVE-100-387585

Entryinfo

Created: 08/10/2026 16:26
Changes: 08/10/2026 16:26 (56)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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