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CVE-2026-85272

Open edX Platform: Path traversal via prefix-bypass in safe_extractall Path Validation

4.3 Medium

Open edX Platform enables the authoring and delivery of online learning at any scale. From Aspen.1 until Ulmo and Verawood.1, openedx/core/lib/extract_archive.py uses _is_bad_path to validate safe_extractall targets by comparing resolved path strings with startswith instead of comparing path components. A course author or staff user with course import permission can submit a crafted .tar.gz archive through the import_olx flow initiated by cms.djangoapps.contentstore.views.import_export.import_handler. An archive member can therefore escape into a sibling course staging directory whose name shares the attacker's base64 directory prefix, causing limited cross-tenant file corruption. Zip archives are not practically affected because ZipFile.extractall strips parent traversal segments, and the advisory does not establish arbitrary filesystem writes, file reads, or direct code execution. This issue is fixed in Ulmo and Verawood.1.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

0.48%Up 0.1 points since Sep 19, 2026
90%50%10%1%

What each source reports

CVE List Score used 4.3

Open edX Platform: Path traversal via prefix-bypass in safe_extractall Path Validation

Open edX Platform enables the authoring and delivery of online learning at any scale. From Aspen.1 until Ulmo and Verawood.1, openedx/core/lib/extract_archive.py uses _is_bad_path to validate safe_extractall targets by comparing resolved path strings with startswith instead of comparing path components. A course author or staff user with course import permission can submit a crafted .tar.gz archive through the import_olx flow initiated by cms.djangoapps.contentstore.views.import_export.import_handler. An archive member can therefore escape into a sibling course staging directory whose name shares the attacker's base64 directory prefix, causing limited cross-tenant file corruption. Zip archives are not practically affected because ZipFile.extractall strips parent traversal segments, and the advisory does not establish arbitrary filesystem writes, file reads, or direct code execution. This issue is fixed in Ulmo and Verawood.1.

Record
CVE-2026-85272
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-22
Updated
2026-11-02
EUVDEUVD-2026-83399 4.3

Open edX Platform enables the authoring and delivery of online learning at any scale. From Aspen.1 until Ulmo and Verawood.1, openedx/core/lib/extract_archive.py uses _is_bad_path to validate safe_extractall targets by comparing resolved path strings with startswith instead of comparing path components. A course author or staff user with course import permission can submit a crafted .tar.gz archive through the import_olx flow initiated by cms.djangoapps.contentstore.views.import_export.import_handler. An archive member can therefore escape into a sibling course staging directory whose name shares the attacker's base64 directory prefix, causing limited cross-tenant file corruption. Zip archives are not practically affected because ZipFile.extractall strips parent traversal segments, and the advisory does not establish arbitrary filesystem writes, file reads, or direct code execution. This issue is fixed in Ulmo and Verawood.1.

Record
EUVD-2026-83399
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Updated
2026-11-02
NVD 4.3

Open edX Platform enables the authoring and delivery of online learning at any scale. From Aspen.1 until Ulmo and Verawood.1, openedx/core/lib/extract_archive.py uses _is_bad_path to validate safe_extractall targets by comparing resolved path strings with startswith instead of comparing path components. A course author or staff user with course import permission can submit a crafted .tar.gz archive through the import_olx flow initiated by cms.djangoapps.contentstore.views.import_export.import_handler. An archive member can therefore escape into a sibling course staging directory whose name shares the attacker's base64 directory prefix, causing limited cross-tenant file corruption. Zip archives are not practically affected because ZipFile.extractall strips parent traversal segments, and the advisory does not establish arbitrary filesystem writes, file reads, or direct code execution. This issue is fixed in Ulmo and Verawood.1.

Record
CVE-2026-85272
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-22
Updated
2026-11-02
OSV 4.3

Open edX Platform: Path traversal via prefix-bypass in safe_extractall Path Validation

Open edX Platform enables the authoring and delivery of online learning at any scale. From Aspen.1 until Ulmo and Verawood.1, openedx/core/lib/extract_archive.py uses _is_bad_path to validate safe_extractall targets by comparing resolved path strings with startswith instead of comparing path components. A course author or staff user with course import permission can submit a crafted .tar.gz archive through the import_olx flow initiated by cms.djangoapps.contentstore.views.import_export.import_handler. An archive member can therefore escape into a sibling course staging directory whose name shares the attacker's base64 directory prefix, causing limited cross-tenant file corruption. Zip archives are not practically affected because ZipFile.extractall strips parent traversal segments, and the advisory does not establish arbitrary filesystem writes, file reads, or direct code execution. This issue is fixed in Ulmo and Verawood.1.

Record
CVE-2026-85272
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-22
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-85272 is a medium vulnerability (CVSS 4.3) in Openedx Openedx-platform, published September 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.48%, the 41st percentile. No source names a fixed version.

References

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