How severe is CVE-2021-41945?

CVE-2021-41945 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 high, and availability none.

Is CVE-2021-41945 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41945?

CVE-2021-41945 affects Encode Httpx. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-41945?

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-2021-41945 published?

CVE-2021-41945 was published on 2022-04-28 and last updated on 2026-07-05.

CVE-2021-41945

Q: What is CVE-2021-41945?

Encode OSS httpx < 0.23.0 is affected by improper input validation in `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.

CVE-2021-41945 is a critical-severity vulnerability in Encode Httpx 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-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Encode Httpx
Published: 2022-04-28
Last modified: 2026-07-05

Description

Encode OSS httpx < 0.23.0 is affected by improper input validation in `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.

Frequently asked questions

What is CVE-2021-41945?: Encode OSS httpx < 0.23.0 is affected by improper input validation in `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.
How severe is CVE-2021-41945?: CVE-2021-41945 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 high, and availability none.
Is CVE-2021-41945 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41945?: CVE-2021-41945 affects Encode Httpx. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41945?: 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-2021-41945 published?: CVE-2021-41945 was published on 2022-04-28 and last updated on 2026-07-05.

References

Affected products (1)

cpe:2.3:a:encode:httpx:*:*:*:*:*:python:*:*

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