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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-f3vw-587g-r29g if there is no patch (or I can't update yet)?

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.

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

Path Traversal in sapperGHSA-f3vw-587g-r29g

GHSA-f3vw-587g-r29g is a security vulnerability in sapper. A fix is available for sapper — see the affected versions and patch details below.

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

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.

sappernpm

27Kdownloads / week

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`npm install sapper@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
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

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

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