CVE-2026-54352: Budibase has arbitrary file read by workspace-builder via PWA-zip symlink upload

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes @budibase/server (npm) < 3.39.9, fixed in 3.39.9. Check your lockfile, including transitive dependencies.

What it is

Budibase is an open-source low-code platform. Prior to 3.39.9, POST /api/pwa/process-zip at packages/server/src/api/routes/static.ts:24 accepts a builder-uploaded .zip, extracts it with extract-zip@2.0.1 into a temp directory, then for each entry listed in icons.json validates the icon path, opens it, and streams the bytes into MinIO. The resulting object is served back via GET /api/assets/{appId}/pwa/{uuid}.png. extract-zip@2.0.1 preserves absolute symlink targets when restoring symlink entries. The icon-source validator at packages/server/src/api/controllers/static/index.ts:259-268 resolves the icon source string against baseDir (path.resolve), checks resolvedSrc.startsWith(baseDir + path.sep) against that string, and calls fs.existsSync(resolvedSrc) which follows symbolic links to confirm the target exists. None of the three calls reject symbolic-link entries. packages/backend-core/src/objectStore/objectStore.ts:302 then calls (await fsp.open(path)).createReadStream() on the resolved path. fsp.open follows the symlink, the target file's bytes stream into MinIO, and the response of the asset-fetch endpoint returns those bytes verbatim. Result: a workspace-level builder reads any file the server process can open. This vulnerability is fixed in 3.39.9.

From the GitHub advisory

Summary

POST /api/pwa/process-zip at packages/server/src/api/routes/static.ts:24 accepts a builder-uploaded .zip, extracts it with extract-zip@2.0.1 into a temp directory, then for each entry listed in icons.json validates the icon path, opens it, and streams the bytes into MinIO. The resulting object is served back via GET /api/assets/{appId}/pwa/{uuid}.png.

extract-zip@2.0.1 preserves absolute symlink targets when restoring symlink entries. The icon-source validator at packages/server/src/api/controllers/static/index.ts:259-268 resolves the icon source string against baseDir (path.resolve), checks resolvedSrc.startsWith(baseDir + path.sep) against that string, and calls fs.existsSync(resolvedSrc) which follows symbolic links to confirm the target exists. None of the three calls reject symbolic-link entries, so an entry stored at baseDir/evil.png but pointing at /data/.env passes the gate.

packages/backend-core/src/objectStore/objectStore.ts:302 then calls (await fsp.open(path)).createReadStream() on the resolved path. fsp.open follows the symlink, the target file's bytes stream into MinIO, and the response of the asset-fetch endpoint returns those bytes verbatim.

Result: a workspace-level builder reads any file the server process can open (root inside the default Docker image, including /data/.env with JWTSECRET, INTERNALAPIKEY, MINIO, REDISPASSWORD, COUCHDBPASSWORD, DATABASEURL) by uploading one crafted PWA zip.

Weakness type: CWE-22, CWE-59.

Product: @budibase/server (npm) · Assigned by: GitHub_M · Published: 2026-06-26

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.49% probability of exploitation activity in the next 30 days; percentile 41.

Timeline

• 2026-06-22 — GitHub-reviewed advisory GHSA-w7mq-r738-x278 published (critical)
• 2026-06-26 — CVE record published by GitHub_M
• 2026-06-27 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-w7mq-r738-x278 github.com
2. CVE.org record CVE-2026-54352 cve.org
3. NVD entry CVE-2026-54352 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

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