CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-59885
High (7.5) in pyasn1 pyasn1. EPSS 0.6% chance of exploitation in the next 30 days. Fixed in pyasn1 0.6.4.
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.
Severity
- EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 49% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-400, CWE-407
- Published
- Modified
- Record from
- the NVD, synced
Affected
- pyasn1:pyasn1
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-8ppf-4f7h-5ppj | PyPI | pyasn1 | <0.6.4 | 0.6.4 |
| PYSEC-2026-3456 | PyPI | pyasn1 | <0.6.4 | 0.6.4 |