# CVE-2026-59885: pyasn1: Quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of service

CVE-2026-59885 is fixed in 6 products on 1 platform, first by pypy-pyasn1 0.4.8-1ubuntu0.3, released July 14, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-59885
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0062
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 14, 2026
- Weakness: Uncontrolled Resource Consumption
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-59885

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | pyasn1 Debian 12.15 (bookworm) | 0.4.8-3+deb12u3 | [DEBIAN-CVE-2026-59885](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59885.md) | Jul 31, 2026 |
| Linux | pyasn1 Debian 13.5 (trixie) | 0.6.1-1+deb13u3 | [DEBIAN-CVE-2026-59885](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59885.md) | Jul 31, 2026 |
| Linux | pyasn1 Debian 14 | 0.6.4-1 | [DEBIAN-CVE-2026-59885](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59885.md) | Jul 31, 2026 |
| Linux | pypy-pyasn1 Ubuntu 22.04.1 LTS (jammy) | 0.4.8-1ubuntu0.3 | [pypy-pyasn1 0.4.8-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-pypy-pyasn1-0.4.8-1ubuntu0.3.md) | Jul 14, 2026 |
| Linux | python-pyasn1 opensuse-leap 16.0 | 0.6.1-160000.5.1 | [OPENSUSE-SU-2026:21392-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21392-1.md) | Jul 20, 2026 |
| Linux | python-pyasn1 sles 15.6 | 0.5.0-150400.12.16.1 | [SUSE-SU-2026:3238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3238-1.md) | Jul 24, 2026 |
| Linux | python-pyasn1 sles 15.7 | 0.5.0-150400.12.16.1 | [SUSE-SU-2026:3238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3238-1.md) | Jul 24, 2026 |
| Linux | python-pyasn1 sles 16.0 | 0.6.1-160000.5.1 | [SUSE-SU-2026:22830-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22830-1.md) | Jul 20, 2026 |
| Linux | python-pyasn1-doc amzn 2023 | 0.4.8-4.amzn2023.0.5 | [ALAS2023-2026-2000](https://patchblox.com/security/data/fix/linux/alas2023-2026-2000.md) | Aug 3, 2026 |
| Linux | python3-pyasn1 Ubuntu 22.04.1 LTS (jammy) | 0.4.8-1ubuntu0.3 | [python3-pyasn1 0.4.8-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-pyasn1-0.4.8-1ubuntu0.3.md) | Jul 14, 2026 |
| Linux | python3-pyasn1 Ubuntu 24.04.5 LTS (noble) | 0.4.8-4ubuntu0.3 | [python3-pyasn1 0.4.8-4ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-pyasn1-0.4.8-4ubuntu0.3.md) | Jul 14, 2026 |
| Linux | python3-pyasn1 Ubuntu 26.04.1 LTS (resolute) | 0.6.3-1ubuntu0.1 | [python3-pyasn1 0.6.3-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-pyasn1-0.6.3-1ubuntu0.1.md) | Jul 14, 2026 |
| Linux | python3-pyasn1 amzn 2023 | 0.4.8-4.amzn2023.0.5 | [ALAS2023-2026-2000](https://patchblox.com/security/data/fix/linux/alas2023-2026-2000.md) | Aug 3, 2026 |
| Linux | python3-pyasn1-modules amzn 2023 | 0.4.8-4.amzn2023.0.5 | [ALAS2023-2026-2000](https://patchblox.com/security/data/fix/linux/alas2023-2026-2000.md) | Aug 3, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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