What’s Vulnerable › Vulnerabilities

CVE-2026-55086: Etherpad: Import/export use Math.random() for temp file paths; predictable paths on shared /tmp enable symlink-based file overwrite

• Severity: medium (CVSS 4.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-19 · updated 2026-09-09
• Weakness: CWE-59

Description

Etherpad is a real-time collaborative editor. Prior to 3.1.0, src/node/handler/ImportHandler.ts and src/node/handler/ExportHandler.ts derive temporary filenames from Math.random() and place them in os.tmpdir(). On a host with a shared world-writable temporary directory, a local unprivileged attacker who predicts a filename can precreate a symbolic link to a file writable by the Etherpad process. Subsequent import or export operations can follow the link through fs.writeFile, fs.rename, or document-conversion output and overwrite the target with partially attacker-controlled content. This issue is fixed in version 3.1.0.

Affected products

• etherpad: before 3.1.0

References

• https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996
• https://github.com/ether/etherpad/pull/7784
• https://github.com/ether/etherpad/releases/tag/v3.1.0
• https://github.com/ether/etherpad/security/advisories/GHSA-2jwf-f4xq-f24h
• https://github.com/ether/etherpad/security/advisories/GHSA-2jwf-f4xq-f24h

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