CVE-2023-41105Public exploit

Path allowlist bypass via null-byte truncation

Published Aug 23, 2023 · Updated Oct 3, 2024

Path normalization in Python Software Foundation CPython 3.11.0 through 3.11.4 allows attackers to bypass path allowlists with null-byte paths. The POSIX C accelerator behind os.path.normpath() stops normalization at the first embedded null byte instead of processing the full input. Exploitation requires an application to allowlist a path before normalization and then use the shortened path, causing access to a different file or directory.

CVSS severity7.5
High
EPSS probability2.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path normalization in Python Software Foundation CPython 3.11.0 through 3.11.4 allows attackers to bypass path allowlists with null-byte paths. The POSIX C accelerator behind os.path.normpath() stops normalization at the first embedded null byte instead of processing the full input. Exploitation requires an application to allowlist a path before normalization and then use the shortened path, causing access to a different file or directory.

The record

CVE
CVE-2023-41105
Published
Aug 23, 2023
Updated
Oct 3, 2024
Vendor
Python Software Foundation
Product
CPython
Classifications
CWE-426
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.11 <=3.11.4

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Python Software Foundation · CPythonversion=3.11 <=3.11.4

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-426Untrusted Search Path

Public exploit references

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Technologies

Your stack

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Your stack

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