How severe is CVE-2026-30922?

CVE-2026-30922 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-30922 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-30922?

CVE-2026-30922 affects Pyasn1. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-30922?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-30922 have an EU (EUVD) identifier?

Yes. CVE-2026-30922 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12747.

When was CVE-2026-30922 published?

CVE-2026-30922 was published on 2026-03-18 and last updated on 2026-06-17.

CVE-2026-30922

CVE-2026-30922 is a high-severity vulnerability in Pyasn1 with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-674.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12747
Weakness: CWE-674
Affected product: Pyasn1
Published: 2026-03-18
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-30922?: 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.
How severe is CVE-2026-30922?: CVE-2026-30922 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-30922 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-30922?: CVE-2026-30922 affects Pyasn1. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-30922?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-30922 have an EU (EUVD) identifier?: Yes. CVE-2026-30922 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12747.
When was CVE-2026-30922 published?: CVE-2026-30922 was published on 2026-03-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:pyasn1:pyasn1:*:*:*:*:*:python:*:*

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