CVE-2026-31827 HIGH

CVE-2026-31827: Alienbin: TTL Index Race Condition allows unauthorized deletion of other users data

Vendor Blue-B
Product Alienbin
Weakness CWE-362
Published March 10, 2026
Last update March 11, 2026

CVSS base score

7.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Alienbin is an anonymous code and text sharing web service. In 1.0.0 and earlier, the /save endpoint in server.js drops and recreates the MongoDB TTL index on the entire post collection for every new paste submission. When User B submits a paste with a short TTL (e.g., 30 seconds), the TTL index is recreated with expireAfterSeconds: 30 for all documents in the collection. This causes User A's paste (originally set to 7 days) to be deleted after 30 seconds. An attacker can intentionally delete all existing pastes by repeatedly submitting pastes with ttlOption=30s.

Key dates

02Disclosure timeline

March 10, 2026 CVE published
March 11, 2026 Record updated