Vulnerability in pyasn1 (UBUNTU-CVE-2026-30922)
Summary
Vulnerability in pyasn1 (UBUNTU-CVE-2026-30922). Risk of unauthorized operations or information disclosure. Exploitable via pyasn1. Mitigation: upgrade to 0.1.7-1ubuntu2.1+esm1 or later.
Original description
The description as published by the source.
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.
Source: OSV.dev (Open Source Vulnerabilities) OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as UBUNTU-CVE-2026-30922 has been found in pyasn1.
Attackers can target a specific entry point like pyasn1 over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade pyasn1 to 0.1.7-1ubuntu2.1+esm1 or later.
If unsure, ask your IT team or search "pyasn1 UBUNTU-CVE-2026-30922" on the vendor's site.
UBUNTU-CVE-2026-30922 (pyasn1)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: pyasn1 / SEQUENCE / SET / RecursionError
Patched: 0.1.7-1ubuntu2.1+esm1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in pyasn1. Attackers reach the vulnerable code path via pyasn1 without authentication.
Check the vendor advisory for the affected versions of pyasn1. Attack surface: pyasn1 / SEQUENCE / SET / RecursionError.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 0.1.7-1ubuntu2.1+esm1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'pyasn1' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'pyasn1' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
pyasn1を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade pyasn1 to 0.1.7-1ubuntu2.1+esm1ステージング環境で 0.1.7-1ubuntu2.1+esm1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory ubuntu.com
- advisory ubuntu.com
- report ubuntu.com
- report cve.org
- report github.com