CVE-2026-128238
Received Received - Intake

Scapy ASN.1 Parser RecursionError in BER Decoder

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: VulnCheck

Description
Scapy before 2.8.0 contains an uncontrolled recursion vulnerability in the BER/ASN.1 decoder in scapy/asn1/ber.py that allows unauthenticated remote attackers to crash parsing applications. Attackers can send a single 833-byte packet with 250 nested ASN.1 SEQUENCE structures to trigger an unhandled RecursionError, terminating TLS, SNMP, X.509, or LDAP parsers even with safe=True.

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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-2026-128238
EUVD
EUVD-2026-125054

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
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-674 The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.

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Executive Summary

Scapy before version 2.8.0 has an uncontrolled recursion flaw in its BER/ASN.1 decoder. Attackers can exploit this by sending a specially crafted 833-byte packet with 250 nested ASN.1 SEQUENCE structures, causing a RecursionError that crashes applications parsing TLS, SNMP, X.509, or LDAP protocols even when safe mode is enabled.

Impact Analysis

This vulnerability allows unauthenticated remote attackers to crash applications that rely on Scapy for parsing network protocols like TLS, SNMP, X.509, or LDAP. This could lead to denial-of-service conditions, disrupting services that depend on these protocols.

Mitigation Strategies

Upgrade Scapy to version 2.8.0 or later to address the uncontrolled recursion vulnerability in the BER/ASN.1 decoder.

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