Summary
Code Extension Marketplace: Zip Slip Path Traversal
Zip Slip Path Traversal in coder/code-marketplace
A Zip Slip (CWE-22) vulnerability in coder/code-marketplace ≤ v2.4.1 allowed a malicious VSIX file to write arbitrary files outside the extension directory. ExtractZip passed raw zip entry names to a callback that wrote files via filepath.Join with no boundary check; filepath.Join resolved .. components but did not prevent the result from escaping the base path.
Root Cause
ExtractZip passed the raw, attacker-controlled zf.Name to a caller-supplied callback:
return false, fn(zf.Name, zr) // zf.Name not sanitized
AddExtension constructed the output path with filepath.Join and no boundary check:
path := filepath.Join(dir, name) // zip loop
path := filepath.Join(dir, file.RelativePath) // extra files loop
filepath.Clean resolved .. lexically but did not confine the result to dir:
filepath.Join("/srv/ext/pub/1.0", "../../../../etc/cron.d/evil")
→ "/etc/cron.d/evil"
Attack Scenario
An authenticated user (any upload-capable role) would submit a VSIX containing path-traversal entries.
On extraction, files would land at attacker-chosen paths writable by the marketplace process, enabling persistence (cron/init injection), SSH key injection, ld.so.preload hijacking, or binary overwrite depending on process privileges.
Recognition
Coder would like to thank Kandlaguduru Vamsi for responsibly disclosing this issue in accordance with https://coder.com/security/policy
Impact
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-35454? CVE-2026-35454 is a high-severity path traversal vulnerability in github.com/coder/code-marketplace (go), affecting versions < 1.2.3-0.20260402184705-988440dee05f. It is fixed in 1.2.3-0.20260402184705-988440dee05f. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- Which versions of github.com/coder/code-marketplace are affected by CVE-2026-35454? github.com/coder/code-marketplace (go) versions < 1.2.3-0.20260402184705-988440dee05f is affected.
- Is there a fix for CVE-2026-35454? Yes. CVE-2026-35454 is fixed in 1.2.3-0.20260402184705-988440dee05f. Upgrade to this version or later.
- Is CVE-2026-35454 exploitable, and should I be worried? Whether CVE-2026-35454 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-35454 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-35454? Upgrade
github.com/coder/code-marketplaceto 1.2.3-0.20260402184705-988440dee05f or later.