CVE-2021-41945Public exploitNetwork attack vector

SSRF and credential disclosure via URL reparsing

Published Apr 28, 2022 · Updated Jul 9, 2026

SSRF in Encode OSS httpx before 0.23.0 allows context-dependent attackers to redirect requests or expose URL credentials via crafted URLs. URL.copy_with serialized a modified URI reference with unsplit() and reparsed it, allowing delimiters in malformed components to shift unchanged URL fields. Exploitation requires a consuming application to pass attacker-controlled URL data into affected URL, Client, or Proxy paths; requests can reach unintended hosts or expose credentials.

CVSS severity9.3
Critical
EPSS probability2.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Encode OSS httpx before 0.23.0 allows context-dependent attackers to redirect requests or expose URL credentials via crafted URLs. URL.copy_with serialized a modified URI reference with unsplit() and reparsed it, allowing delimiters in malformed components to shift unchanged URL fields. Exploitation requires a consuming application to pass attacker-controlled URL data into affected URL, Client, or Proxy paths; requests can reach unintended hosts or expose credentials.

The record

CVE
CVE-2021-41945
Published
Apr 28, 2022
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:N
9.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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