How severe is CVE-2026-23490?

CVE-2026-23490 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-2026-23490 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23490?

CVE-2026-23490 primarily affects Pyasn1. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-23490?

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-2026-23490 have an EU (EUVD) identifier?

Yes. CVE-2026-23490 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-2865.

When was CVE-2026-23490 published?

CVE-2026-23490 was published on 2026-01-16 and last updated on 2026-06-30.

CVE-2026-23490

CVE-2026-23490 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-2865
Weakness: CWE-770
Affected product: Pyasn1
Published: 2026-01-16
Last modified: 2026-06-30

Description

pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.2, a Denial-of-Service issue has been found that leads to memory exhaustion from malformed RELATIVE-OID with excessive continuation octets. This vulnerability is fixed in 0.6.2.

Frequently asked questions

What is CVE-2026-23490?: pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.2, a Denial-of-Service issue has been found that leads to memory exhaustion from malformed RELATIVE-OID with excessive continuation octets. This vulnerability is fixed in 0.6.2.
How severe is CVE-2026-23490?: CVE-2026-23490 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-2026-23490 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23490?: CVE-2026-23490 primarily affects Pyasn1. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-23490?: 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-2026-23490 have an EU (EUVD) identifier?: Yes. CVE-2026-23490 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-2865.
When was CVE-2026-23490 published?: CVE-2026-23490 was published on 2026-01-16 and last updated on 2026-06-30.

References

Affected products (2)

cpe:2.3:a:pyasn1:pyasn1:*:*:*:*:*:python:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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