CVE-2026-59885
High
Description
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductPyasn1
PublishedJul 14, 2026
First seenJul 14, 2026
How to fix
Update
- pyasn1 pyasn10.6.4 or later
- pyasn10.6.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| pyasn1 pyasn1 | v < 0.6.4 | 0.6.4 |
| pyasn1PyPI | v < 0.6.4 | 0.6.4 |
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