How severe is CVE-2020-36242?

CVE-2020-36242 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2020-36242 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-36242?

CVE-2020-36242 primarily affects Cryptography.io Cryptography. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-36242?

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

When was CVE-2020-36242 published?

CVE-2020-36242 was published on 2021-02-07 and last updated on 2026-06-17.

CVE-2020-36242

CVE-2020-36242 is a critical-severity vulnerability in Cryptography.io Cryptography with a CVSS 3.x base score of 9.1. 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-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Cryptography.io Cryptography
Published: 2021-02-07
Last modified: 2026-06-17

Description

In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.

Frequently asked questions

What is CVE-2020-36242?: In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.
How severe is CVE-2020-36242?: CVE-2020-36242 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2020-36242 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-36242?: CVE-2020-36242 primarily affects Cryptography.io Cryptography. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-36242?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-36242 published?: CVE-2020-36242 was published on 2021-02-07 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:cryptography.io:cryptography:*:*:*:*:*:python:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:1.10.0:*:*:*:*:*:*:*

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