Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Pyasn1 | Pyasn1 | < 0.6.3 |
Related Weaknesses (CWE)
References
- https://github.com/pyasn1/pyasn1/commit/25ad481c19fdb006e20485ef3fc2e5b3eff30ef0Patch
- https://github.com/pyasn1/pyasn1/security/advisories/GHSA-jr27-m4p2-rc6rExploitVendor Advisory
- http://www.openwall.com/lists/oss-security/2026/03/20/4
- https://lists.debian.org/debian-lts-announce/2026/05/msg00001.html
FAQ
What is CVE-2026-30922?
CVE-2026-30922 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 deep...
How severe is CVE-2026-30922?
CVE-2026-30922 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-30922?
Check the references section above for vendor advisories and patch information. Affected products include: Pyasn1 Pyasn1.