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CVE-2026-30922

pyasn1 Vulnerable to Denial of Service via Unbounded Recursion

Published: Mar 18, 2026Updated: May 1, 2026 Sources: CVE List NVD BDUCWE-674
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.6%
Top 56.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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 Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-674

Affected Products

Red Hat Enterprise LinuxRed Hat Inc.
On-premOS
Operating Systems / linux-distro
Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
Red Hat Ansible Automation PlatformRed Hat Inc.
On-premDesktop App
DevTools & CI / ide-editor
РЕД ОСООО «Ред Софт»
On-premOS
Operating Systems / linux-distro
Red Hat AI Inference ServerRed Hat Inc.
SaaSSaaS Service
AI / ML / llm-serving-inference
red hat inc.commercialUSOperating Systemsaka red hat
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
ооо «ред софт»commercialRUOperating Systemsaka red soft
and 2 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

http://www.openwall.com/lists/oss-security/2026/03/20/4
openwall.com
https://github.com/pyasn1/pyasn1
github.com
https://github.com/pyasn1/pyasn1/commit/25ad481c19fdb006e20485ef3fc2e5b3eff30ef0
github.com
and 10 more references View all →

Timeline

Published
Mar 18, 2026
Last Updated
May 1, 2026

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