CVE-2026-30922 | pyasn1 Vulnerable to Denial of Service via Unbounded Recursion

Exp

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.

Published: 2026-03-18 Last update: 2026-05-01 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-30922 is rated Exploit Available (50/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-30922

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-30922

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-01 0.05% 0.02% -0.03%
2 2026-04-19 0.05% 0.05% +0.01%
3 2026-03-24 — 0.05% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-30922

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-30922

GitHub Security Advisory for CVE-2026-30922

GHSA-jr27-m4p2-rc6r · Severity: high · Ecosystem: pip — Denial of Service in pyasn1 via Unbounded Recursion

OS Trackers for CVE-2026-30922

vendor priority summary link
debian not yet assigned CVE-2026-30922 not yet assigned priority: Debian including 1 source packages (pyasn1), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-30922
redhat high — https://access.redhat.com/security/cve/CVE-2026-30922
suse high CVE-2026-30922 severity important: SUSE including 253 source package names (13.2-9.31:gpg2-2.4.4-slfo.1.1_8.1, 13.2-9.31:libpython3_11-1_0-3.11.13-2.1, …), 360 product×package rows across 82 product lines (Container suse/manager/4.3/proxy-httpd, Container suse/manager/4.3/proxy-tftpd, … (82 product lines)): Known Affected 231, Fixed 128, First Fixed 1. https://www.suse.com/security/cve/CVE-2026-30922/
ubuntu medium CVE-2026-30922 medium priority: Ubuntu including 1 source packages (pyasn1), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): released 8. https://ubuntu.com/security/CVE-2026-30922

Affected software / configurations for CVE-2026-30922

Vendor Product Version Raw CPE
pyasn1 pyasn1 < 0.6.3 cpe:2.3:a:pyasn1:pyasn1:*:*:*:*:*:python:*:*

References for CVE-2026-30922

cvelogic Threat Intelligence