How severe is CVE-2026-35454?

No CVSS score has been assigned to CVE-2026-35454 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-35454?

CVE-2026-35454 affects the following packages: github.com/coder/code-marketplace (Go). Ecosystems affected: Go.

How do I fix CVE-2026-35454?

Update github.com/coder/code-marketplace to 1.2.3-0.20260402184705-988440dee05f or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35454 is resolved across your whole dependency graph.

How do I detect CVE-2026-35454 in my Go dependencies?

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

How do I mitigate CVE-2026-35454 if there is no patch (or I can't update yet)?

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.

How does O3 Security protect against CVE-2026-35454?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-35454 can be triaged on real exposure rather than presence alone.

Is CVE-2026-35454 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-35454 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-35454?

CVE-2026-35454 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 28th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-35454?

CVE-2026-35454 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-35454 published, and has it been updated?

CVE-2026-35454 was published on April 6, 2026 and was last updated on August 29, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-35454 — code-marketplace

Fix: coder/code-marketplace@988440d

CVE-2026-35454 is a Path Traversal vulnerability in github.com/coder/code-marketplace. A fix is available for github.com/coder/code-marketplace — see the affected versions and patch details below.

Code Extension Marketplace has a Zip Slip Path Traversal

Also known asGHSA-8x9r-hvwg-c55hGO-2026-5270

Published

Apr 6, 2026

Updated

Aug 29, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
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-2026-35454.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs28th percentile — riskier than 28% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

🐹github.com/coder/code-marketplace

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

Description

Zip Slip Path Traversal in coder/code-marketplace

Summary

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.

Fix

Addressed in https://github.com/coder/code-marketplace/releases/tag/v2.4.2

Recognition

Coder would like to thank Kandlaguduru Vamsi for responsibly disclosing this issue in accordance with https://coder.com/security/policy

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/coder/code-marketplace`	all versions	1.2.3-0.20260402184705-988440dee05f`go get github.com/coder/code-marketplace@v1.2.3-0.20260402184705-988440dee05f`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/coder/code-marketplace, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/coder/code-marketplace to 1.2.3-0.20260402184705-988440dee05f or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35454 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-35454 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-35454. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Zip Slip Path Traversal in coder/code-marketplace ## Summary 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: ```go return false, fn(zf.Name, zr) // zf.Name not

O3 Security · Impact-Aware SCA

Is CVE-2026-35454 in your dependencies?

O3 Security finds CVE-2026-35454 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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