Description
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| pyasn1 | pyasn1 | < 0.6.4 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pyasn1 | 0.6.4-1 | — |
| Debian 13 | pyasn1 | 0.6.1-1+deb13u3 | — |
| Debian 12 | pyasn1 | 0.4.8-3+deb12u3 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | pyasn1 | 0.6.4-1ubuntu0.1 | USN-9011-1 |
| Ubuntu 26.04 LTS | pyasn1 | 0.6.3-1ubuntu0.1 | USN-9011-1, USN-8712-1 |
| Ubuntu 24.04 LTS | pyasn1 | 0.4.8-4ubuntu0.3 | USN-9011-1, USN-8712-1 |
| Ubuntu 22.04 LTS | pyasn1 | 0.4.8-1ubuntu0.3 | USN-9011-1, USN-8712-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | pyasn1 | 0.4.2-3ubuntu0.20.04.1~esm2 | USN-9011-1 |
| Ubuntu Pro 18.04 LTS | pyasn1 | 0.4.2-3ubuntu0.18.04.1~esm2 | USN-9011-1 |
| Ubuntu Pro 16.04 LTS | pyasn1 | 0.1.9-1ubuntu0.1~esm2 | USN-9011-1 |
| Ubuntu Pro 14.04 LTS | pyasn1 | 0.1.7-1ubuntu2.1+esm2 | USN-9011-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | jaeger | 2.19.0-1.1.hum1 | RHSA-2026:40236 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLES 15 SP5 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLES 15 SP4 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLES 3 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | python-pyasn1 | 0.6.1-160000.5.1 | SUSE-SU-2026:22830-1 |
| SLES for SAP 15 SP6 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLES for SAP 15 SP5 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLES for SAP 15 SP4 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLES 16.0 | python-pyasn1 | 0.6.1-160000.5.1 | SUSE-SU-2026:22830-1 |
| SLE Micro 6.2 | python-pyasn1 | 0.6.1-160000.5.1 | SUSE-SU-2026:22765-1 |
| SLE Micro 6.1 | python-pyasn1 | 0.5.0-slfo.1.1_4.1 | SUSE-SU-2026:23167-1 |
| SLE Micro 6.0 | python-pyasn1 | 0.5.0-5.1 | SUSE-SU-2026:23006-1 |
| SLE HPC 15 SP5 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
| SLE HPC 15 SP4 | python-pyasn1 | 0.5.0-150400.12.16.1 | SUSE-SU-2026:3238-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-pyasn1 | 0.6.4-1.1 | openSUSE-SU-2026:11318-1 |
| openSUSE Leap 16.0 | python-pyasn1 | 0.6.1-160000.5.1 | openSUSE-SU-2026:21392-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | python3-pyasn1 +2 | 0.4.8-4.amzn2023.0.5 | ALAS2023-2026-2000 |
| Amazon Linux 2 | python2-pyasn1 +3 | 0.1.9-7.amzn2.0.5 | ALAS2-2026-3836 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python-pyasn1 | 0.4.8-3 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | airflow-3 | 3.3.0-r4 | — |
| Wolfi rolling | datadog-agent-7.72-core-integrations | No fix yet | — |
| Wolfi rolling | kserve +1 | 0.20.0-r7 | — |
| Wolfi rolling | kserve-storage-controller | 0.19.0-r5 | — |
| Wolfi rolling | kubeflow-pipelines-apiserver | 2.17.0-r4 | — |
| Wolfi rolling | kubeflow-pipelines-metadata-writer-compat | 2.17.2-r4 | — |
| Wolfi rolling | py3-cassandra-medusa | 0.29.1-r1 | — |
| Wolfi rolling | superset-6.0 | 6.0.0-r15 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | pyasn1 | < 0.6.4 | 0.6.4 | GHSA-m4p7-r5rc-7g4j |
Advisories 12
- USN-9011-1 pyasn1 vulnerabilities Ubuntu Security Notices (USN) · Nov 11, 2026
- RHSA-2026:40236 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- USN-8712-1 pyasn1 vulnerabilities Ubuntu Security Notices (USN) · Sep 2, 2026
- SUSE-SU-2026:23167-1 Security update for python-pyasn1 SUSE / openSUSE Security Updates · Aug 22, 2026
- SUSE-SU-2026:23006-1 Security update for python-pyasn1 SUSE / openSUSE Security Updates · Aug 12, 2026
- ALAS2-2026-3836 Important: python-pyasn1 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Aug 4, 2026
- ALAS2023-2026-2000 Important: python-pyasn1 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 4, 2026
- SUSE-SU-2026:3238-1 Security update for python-pyasn1 SUSE / openSUSE Security Updates · Jul 28, 2026
- SUSE-SU-2026:22830-1 Security update for python-pyasn1 SUSE / openSUSE Security Updates · Jul 28, 2026
- openSUSE-SU-2026:21392-1 Security update for python-pyasn1 SUSE / openSUSE Security Updates · Jul 24, 2026
- SUSE-SU-2026:22765-1 Security update for python-pyasn1 SUSE / openSUSE Security Updates · Jul 23, 2026
- openSUSE-SU-2026:11318-1 python313-pyasn1-0.6.4-1.1 on GA media SUSE / openSUSE Security Updates · Jul 21, 2026