CVE-2026-30922

HIGH

7.5

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.

CVE Details

CVSS v3.1 Score7.5

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/18/2026

Last Modified3/21/2026

Sourcenvd

Honeypot Sightings0

Affected Products

pyasn1:pyasn1

Weaknesses (CWE)

CWE-674

References

https://github.com/pyasn1/pyasn1/commit/25ad481c19fdb006e20485ef3fc2e5b3eff30ef0(security-advisories@github.com)

https://github.com/pyasn1/pyasn1/security/advisories/GHSA-jr27-m4p2-rc6r(security-advisories@github.com)

http://www.openwall.com/lists/oss-security/2026/03/20/4(af854a3a-2127-422b-91ae-364da2661108)

IOC Correlations

No correlations recorded

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