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Not in CISA KEV
HIGH severity

CVE-2021-41279 — basercms

HIGHFix: baserproject/basercms@d8ab0a8

CVE-2021-41279 is a high-severity (CVSS 8.8) Path Traversal vulnerability in baserproject/basercms. A fix is available for baserproject/basercms — see the affected versions and patch details below.

Potential Zip Slip Vulnerability in baserCMS

Also known asGHSA-4x2f-54wr-4hjg
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs75th percentile — riskier than 75% of all scored CVEsHighest risk
0.00%0.71%1.41%2.12%0.4%1.6%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-41279 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐘baserproject/basercms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

BaserCMS is an open source content management system with a focus on Japanese language support. In affected versions users with upload privilege may upload crafted zip files capable of path traversal on the host operating system. This is a vulnerability that needs to be addressed when the management system is used by an unspecified number of users. If you are eligible, please update to the new version as soon as possible.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistbaserproject/basercmsall versions4.5.4composer require baserproject/basercms:^4.5.4

Affected Products

1 product · 1 configurations
Application
basercmsbasercms
< 4.5.4
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for baserproject/basercms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update baserproject/basercms to 4.5.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41279 is resolved across your whole dependency graph.

  3. Workarounds

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

BaserCMS is an open source content management system with a focus on Japanese language support. In affected versions users with upload privilege may upload crafted zip files capable of path traversal on the host operating system. This is a vulnerability that needs to be addressed when the management system is used by an unspecified number of users. If you are eligible, please update to the new version as soon as possible.
O3 Security · Impact-Aware SCA

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CVE-2021-41279: basercms Path Traversal — Fixed in 4.5.4