How severe is GHSA-f3vw-587g-r29g?

No CVSS score has been assigned to GHSA-f3vw-587g-r29g yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-f3vw-587g-r29g?

GHSA-f3vw-587g-r29g affects the following packages: sapper (npm). Ecosystems affected: npm.

How do I fix GHSA-f3vw-587g-r29g?

Update sapper to 0.27.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f3vw-587g-r29g is resolved across your whole dependency graph.

How do I detect GHSA-f3vw-587g-r29g in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sapper. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-f3vw-587g-r29g 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 GHSA-f3vw-587g-r29g?

O3 pinpoints whether GHSA-f3vw-587g-r29g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-f3vw-587g-r29g actively exploited in the wild?

No public exploit code has been indexed for GHSA-f3vw-587g-r29g 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.

When was GHSA-f3vw-587g-r29g published, and has it been updated?

GHSA-f3vw-587g-r29g was published on September 3, 2020 and was last updated on August 31, 2020. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

GHSA-f3vw-587g-r29g

GHSA-f3vw-587g-r29g is a security vulnerability in sapper. O3 Security confirms whether GHSA-f3vw-587g-r29g is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Path Traversal in sapper

Published

Sep 3, 2020

Updated

Aug 31, 2020

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 31, 2020 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

📦sapper

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

Description

Versions of sapper prior to 0.27.11 are vulnerable to Path Traversal. It is possible to access sensitive files on the server through HTTP requests containing URL-encoded ../.

You may test a sapper application running in prod mode with curl -vvv http://localhost:3000/client/750af05c3a69ddc6073a/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/etc/passwd.

Recommendation

Upgrade to version 0.27.11 or later.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`sapper`	all versions	0.27.11

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sapper. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update sapper to 0.27.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f3vw-587g-r29g 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 pinpoints whether GHSA-f3vw-587g-r29g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-f3vw-587g-r29g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Versions of `sapper` prior to 0.27.11 are vulnerable to Path Traversal. It is possible to access sensitive files on the server through HTTP requests containing URL-encoded `../`. You may test a `sapper` application running in prod mode with `curl -vvv http://localhost:3000/client/750af05c3a69ddc6073a/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/etc/passwd`. ## Recommendation Upgrade to version 0.27.11 or later.

O3 Security · Impact-Aware SCA

Is GHSA-f3vw-587g-r29g in your dependencies?

O3 detects GHSA-f3vw-587g-r29g across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works