Vulnerability Details CVE-2026-59885
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue is fixed in version 0.6.4.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 26.2%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2026-59885
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cpe:2.3:a:pyasn1:pyasn1:0.2.1
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cpe:2.3:a:pyasn1:pyasn1:0.2.2
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cpe:2.3:a:pyasn1:pyasn1:0.2.3
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cpe:2.3:a:pyasn1:pyasn1:0.3.1
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cpe:2.3:a:pyasn1:pyasn1:0.3.2
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cpe:2.3:a:pyasn1:pyasn1:0.3.3
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cpe:2.3:a:pyasn1:pyasn1:0.3.4
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cpe:2.3:a:pyasn1:pyasn1:0.3.5
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cpe:2.3:a:pyasn1:pyasn1:0.3.6
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cpe:2.3:a:pyasn1:pyasn1:0.3.7
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cpe:2.3:a:pyasn1:pyasn1:0.4.1
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cpe:2.3:a:pyasn1:pyasn1:0.4.2
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cpe:2.3:a:pyasn1:pyasn1:0.4.3
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cpe:2.3:a:pyasn1:pyasn1:0.4.4
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cpe:2.3:a:pyasn1:pyasn1:0.4.5
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cpe:2.3:a:pyasn1:pyasn1:0.4.6
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cpe:2.3:a:pyasn1:pyasn1:0.4.7
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cpe:2.3:a:pyasn1:pyasn1:0.4.8
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cpe:2.3:a:pyasn1:pyasn1:0.5.0
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cpe:2.3:a:pyasn1:pyasn1:0.5.1
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cpe:2.3:a:pyasn1:pyasn1:0.6.0
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cpe:2.3:a:pyasn1:pyasn1:0.6.1
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cpe:2.3:a:pyasn1:pyasn1:0.6.2
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cpe:2.3:a:pyasn1:pyasn1:0.6.3