CVE-2026-128237
Received Received - Intake

Denial of Service in Scapy via OID Parsing

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: VulnCheck

Description
Scapy before 2.8.0 contains a denial of service vulnerability in BER_num_dec() and BERcodec_OID.do_dec() that allows remote attackers to exhaust CPU by supplying oversized OID arcs. Attackers can send ASN.1/BER data with many base-128 continuation bytes to cause quadratic CPU consumption or an uncaught ValueError crash on Python 3.11+.

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Meta Information

Published
2026-11-13
Last Modified
2026-11-13
Generated
2026-11-13
AI Q&A
2026-11-13
EPSS Evaluated
N/A
NVD
CVE-2026-128237
EUVD
EUVD-2026-125055

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
scapy scapy to 2.8.0 (exc)
secdev scapy to 2.8.0 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-407 An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

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Executive Summary

Scapy before version 2.8.0 has a denial of service vulnerability in the BER_num_dec() and BERcodec_OID.do_dec() functions. Attackers can send specially crafted ASN.1/BER data with oversized OID arcs, causing excessive CPU usage due to quadratic time complexity or crashing the application with a ValueError on Python 3.11 and later.

Detection Guidance

Detecting this vulnerability requires monitoring for unusual CPU usage spikes or crashes when processing ASN.1/BER data. Use network monitoring tools to inspect traffic for oversized OID arcs. Check Scapy logs for ValueError exceptions on Python 3.11+ systems. No specific commands are provided in the context.

Impact Analysis

This vulnerability allows remote attackers to disrupt services by consuming excessive CPU resources, leading to degraded performance or complete denial of service. Systems using Scapy for network analysis or packet manipulation could become unresponsive when processing malicious input.

Mitigation Strategies

Upgrade Scapy to version 2.8.0 or later to address the vulnerability. If upgrading is not possible, restrict network access to systems running Scapy or filter ASN.1/BER traffic with oversized OID arcs. Monitor CPU usage for abnormal spikes.

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