# CVE-2026-30922: pyasn1 Vulnerable to Denial of Service via Unbounded Recursion > Attackers can crash applications using pyasn1 by sending deeply nested ASN.1 data, causing uncontrolled recursion and resource exhaustion. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 18 Mar 2026 - **Updated:** 17 Sep 2026 - **Also known as:** ALSA-2026:13902, ALSA-2026:13917, AZL-80238, BELL-CVE-2026-30922, CLEANSTART-2026-BW26261, CLEANSTART-2026-HQ36260, DEBIAN-CVE-2026-30922, ECHO-b1bf-5a18-ca74, GHSA-jr27-m4p2-rc6r, MGASA-2026-0087, MINI-2h75-8x42-8g23, MINI-2hjq-jmjw-w87v, MINI-95ch-cw4g-j7w3, MINI-cgwm-24qr-7rh6, MINI-cjw8-9wwv-6v58, MINI-f3p5-j7jg-rvg6, MINI-f5j2-f7rp-3c5q, MINI-hrmp-qfwg-h782, MINI-mfrp-m8qv-4fx8, MINI-p2jp-xgx3-x8fg, MINI-pq4f-vh5f-8hgv, MINI-q27c-83cq-x94p, MINI-w45r-vx8m-7fcr, OESA-2026-1775, OESA-2026-1776, OESA-2026-1779, OESA-2026-1780, OESA-2026-2764, OESA-2026-2765, PYSEC-2026-2263, RHSA-2026:13902, RHSA-2026:13917, RHSA-2026:20588, RHSA-2026:22131, RHSA-2026:22132, RHSA-2026:22133, RHSA-2026:22134, RHSA-2026:22135, RHSA-2026:22969, RHSA-2026:22970, RHSA-2026:22987, RLSA-2026:13902, RLSA-2026:13917, ROOT-APP-PYPI-CVE-2026-30922, SUSE-SU-2026:1075-1, SUSE-SU-2026:1076-1, SUSE-SU-2026:1158-1, SUSE-SU-2026:20821-1, SUSE-SU-2026:20835-1, SUSE-SU-2026:20878-1, SUSE-SU-2026:20929-1, openSUSE-SU-2026:10393-1, openSUSE-SU-2026:20418-1 ## What is CVE-2026-30922? CVE-2026-30922 is a high-severity denial of service vulnerability in pyasn1, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.3, the `pyasn1` library is vulnerable to a Denial of Service (DoS) attack caused by uncontrolled recursion when decoding ASN.1 data with deeply nested structures. An attacker can supply a crafted payload containing thousands of nested `SEQUENCE` (`0x30`) or `SET` (`0x31`) tags with "Indefinite Length" (`0x80`) markers. This forces the decoder to recursively call itself until the Python interpreter crashes with a `RecursionError` or consumes all available memory (OOM), crashing the host application. This is a distinct vulnerability from CVE-2026-23490 (which addressed integer overflows in OID decoding). The fix for CVE-2026-23490 (`MAX_OID_ARC_CONTINUATION_OCTETS`) does not mitigate this recursion issue. Version 0.6.3 fixes this specific issue. Weakness: CWE-835 (Loop with Unreachable Exit Condition), CWE-674 (Uncontrolled Recursion) ## Which versions are affected by CVE-2026-30922? 3 open source packages ship an affected version, including pyasn1. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `pyasn1` | PyPI | All versions | 0.6.3 | | `pyasn1` | PyPI | All versions | 0.6.3 | | `pyasn1` | PyPI | All versions | 0.6.3 | | `resource-agents` | AlmaLinux:8 | All versions | 4.9.0-54.el8_10.33 | | `resource-agents-aliyun` | AlmaLinux:8 | All versions | 4.9.0-54.el8_10.33 | | `resource-agents-gcp` | AlmaLinux:8 | All versions | 4.9.0-54.el8_10.33 | | `resource-agents-paf` | AlmaLinux:8 | All versions | 4.9.0-54.el8_10.33 | | `fence-agents-aliyun` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-all` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-amt-ws` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-apc` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-apc-snmp` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-aws` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-azure-arm` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-bladecenter` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-brocade` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-cisco-mds` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-cisco-ucs` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-common` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-compute` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-drac5` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-eaton-snmp` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-emerson` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-eps` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-gce` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-heuristics-ping` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-hpblade` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ibm-powervs` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ibm-vpc` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ibmblade` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ifmib` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ilo-moonshot` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ilo-mp` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ilo-ssh` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ilo2` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-intelmodular` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ipdu` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-ipmilan` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-kdump` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | | `fence-agents-kubevirt` | AlmaLinux:9 | All versions | 4.10.0-98.el9_7.13 | Products: Pyasn1 Pyasn1. ## How do I fix CVE-2026-30922? Upgrade pyasn1 to 0.6.3 or later. ## Is CVE-2026-30922 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-30922 exists. ## Other vulnerabilities in pyasn1 - [CVE-2026-59884](https://insights.sbomify.com/CVE-2026-59884/): pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs (high 7.5) - [CVE-2026-59885](https://insights.sbomify.com/CVE-2026-59885/): pyasn1: Quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of service (high 7.5) - [CVE-2026-59886](https://insights.sbomify.com/CVE-2026-59886/): pyasn1: Uncontrolled resource consumption when converting decoded REAL values (high 7.5) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-30922 and fix it if it is affected. What it is: CVE-2026-30922 is a high-severity denial of service vulnerability in pyasn1, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-30922 exists. Affected packages and fixed versions: - pyasn1 (PyPI): affected all versions; fixed in 0.6.3 - pyasn1 (PyPI): affected all versions; fixed in 0.6.3 - pyasn1 (PyPI): affected all versions; fixed in 0.6.3 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-30922/ (Markdown: https://insights.sbomify.com/CVE-2026-30922/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-30922 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-30922 - OSV: https://osv.dev/vulnerability/CVE-2026-30922 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-30922/ Summaries are generated and may contain mistakes; the official description above is the record.