CVE intelligence and bounded remediation

CVE-2023-40587 — Pyramid is an open source Python web framework

Medium CVSS 5.3

Pyramid is an open source Python web framework. A path traversal vulnerability in Pyramid versions 2.0.0 and 2.0.1 impacts users of Python 3.11 that are using a Pyramid static view with a full filesystem path and have a `index.html` file that is located exactly one directory above the location of the static view's file system path. No further path traversal exists, and the only file that could be disclosed accidentally is `index.html`. Pyramid version 2.0.2 rejects any path that contains a null-byte out of caution. While valid in directory/file names, we would strongly consider it a mistake to use null-bytes in naming files/directories. Secondly, Python 3.11, and 3.12 has fixed the underlying issue in `os.path.normpath` to no longer truncate on the first `0x00` found, returning the behavior to pre-3.11 Python, un an as of yet unreleased version. Fixes will be available in:Python 3.12.0rc2 and 3.11.5. Some workarounds are available. Use a version of Python 3 that is not affected, downgrade to Python 3.10 series temporarily, or wait until Python 3.11.5 is released and upgrade to the latest version of Python 3.11 series.

Severity
Medium
CVSS
5.3 (3.1)
Published
2023-08-25
CISA KEV
Not currently listed
Ecosystem
python/pypi
Weaknesses
CWE-22

Affected products

  • agendaless / pyramid
  • fedoraproject / fedora / 38
  • fedoraproject / fedora / 39

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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