# CVE-2026-40162: bugsink β€” Fixed in 2.1.1 🐍 🐍 PyPI Not in CISA KEV HIGH severity # CVE-2026-40162 β€” bugsink HIGH CVE-2026-40162 is a high-severity (CVSS 7.1) Improper Input Validation vulnerability in bugsink. A fix is available for bugsink β€” see the affected versions and patch details below. Bugsink affected by authenticated arbitrary file write in artifactbundle/assemble Also known as[GHSA-8hw4-fhww-273g](/vulnerability/GHSA-8hw4-fhww-273g)PYSEC-2026-2404 Published Apr 10, 2026 Updated Oct 28, 2026 Affected 1 pkg Patched 1 / 1 Exploits None indexed Exploitation data as of Nov 8, 2026 Β· OSV.dev, NVD, FIRST.org (EPSS) ## Exploitation Status ### No confirmed exploitation observed yet - CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment. Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40162. ## EPSS Exploitation Probability [via FIRST.org β†—](https://www.first.org/epss/) 0.3%probability of exploitation in next 30 days Lower Risk+0.01% Lower risk than most CVEs24th percentile β€” riskier than 24% of all scored CVEsHighest risk 0.00%0.34%0.67%1.01%0.1%0.3%May 26Sep 26Nov 26 Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/). ## How urgent is this, really ## Where this sits among everything scored ## Real-World Exposure 1 pkg affected 🐍`bugsink` Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages β€” download data is not available via public APIs for these ecosystems. ## Description ## Authenticated arbitrary file write in artifact bundle assembly ### Summary An authenticated file write vulnerability was identified in Bugsink **2.1.0** in the artifact bundle assembly flow. A user with a valid authentication token could cause the application to write attacker-controlled content to a filesystem location writable by the Bugsink process. This issue requires authentication and affects only version **2.1.0**. The issue is fixed in **2.1.1**. ### Impact This vulnerability allows an authenticated user to create or overwrite files **within locations writable by the Bugsink service account**. The practical impact depends on the deployment environment and filesystem permissions of the running process. Possible consequences include: - modification of application data files - corruption of uploaded assets or temporary files - overwriting files in mounted writable volumes - disruption of normal application behavior No unauthenticated exploitation is known. No direct code execution has been demonstrated as part of this issue, though impact may be greater in deployments where the process has broad write permissions. ### Affected versions - **Affected:** 2.1.0 - **Fixed:** 2.1.1 - **Not affected:** earlier releases ### Mitigation Upgrade to **2.1.1**. As a defense-in-depth measure, deployments should continue to ensure the Bugsink process runs with the **minimum required filesystem permissions**. ## Affected Packages 1 total 1 fixed Ecosystem Package Vulnerable range Fix 🐍PyPI `bugsink` β‰₯ 2.1.0&&< 2.1.1 2.1.1`pip install --upgrade 'bugsink==2.1.1'` ## Affected Products 1 product Β· 1 configurations Application `bugsink`bugsink 1 version 2.1.0 ## Detection & mitigation playbook Open-source dependency 1. ### Detect Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for bugsink, including transitive dependencies β€” a direct dependency you never call can still pull in a vulnerable version. 2. ### Fix Update bugsink to 2.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range β€” O3 confirms CVE-2026-40162 is resolved across your whole dependency graph. 3. ### Workarounds If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. ## Frequently Asked Questions \# Authenticated arbitrary file write in artifact bundle assembly ## Summary An authenticated file write vulnerability was identified in Bugsink \*\*2.1.0\*\* in the artifact bundle assembly flow. A user with a valid authentication token could cause the application to write attacker-controlled content to a filesystem location writable by the Bugsink process. This issue requires authentication and affects only version \*\*2.1.0\*\*. The issue is fixed in \*\*2.1.1\*\*. ## Impact This vulnerability allows an authenticated user to create or overwrite files \*\*within locations writable by the Bugsink ser O3 Security Β· Impact-Aware SCA ### Is CVE-2026-40162 in your dependencies? Find it across PyPI, including transitive dependencies. [Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)