CVE-2026-30922
pyasn1 Vulnerable to Denial of Service via Unbounded Recursion
No known exploitation. EPSS puts it in the 58th percentile. A vendor fix is available.
No public exploit knownFixVendor fixNo build named by the sources
e.g. OID 1.3.6.1.4.1.25623.1.0.136782
What to do
The vendor has published a fix. Version details are below where the sources state them.
- Pyasn1Affected: < 0.6.3Upgrade to: not statedStated by: CVE record
- Red Hat Inc. Red Hat Enterprise LinuxAffected: 8Upgrade to: not statedStated by: BDU
- Сообщество свободного программного обеспечения Debian GNU/LinuxAffected: 11Upgrade to: not statedStated by: BDU
- Red Hat Inc. Red Hat Ansible Automation PlatformAffected: 2.5 for RHEL 8Upgrade to: not statedStated by: BDU
- ООО «Ред Софт» РЕД ОСAffected: 8.0Upgrade to: not statedStated by: BDU
Versions as the sources state them. 2 more products have version data. Full version matrix after sign-in
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.8% chance of exploitation activity in the next 30 days, which ranks it in the 58th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
36 events over 176 days, from the signal feeds we watch.
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Scored 7.5 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
Sources
Watch the software you run.
My Stack ranks new CVEs for your products by real-world exploitation, so the next serious one reaches you without reading every advisory.
We'll flag the next CVE, public exploit or patch for Red Hat Enterprise Linux, not every advisory.
A free account adds
- The full version matrix and every affected product
- Exploit links, proofs of concept and Metasploit modules
- Email alerts for the products you watch
- The same data over REST API, MCP and CLI