CVE-2026-31827 PUBLISHED

Alienbin: TTL Index Race Condition allows unauthorized deletion of other users data

Assigner: GitHub_M
Reserved: 09.03.2026 Published: 10.03.2026 Updated: 10.03.2026

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.

Metrics

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
CVSS Score: 7.1

Product Status

Vendor Blue-B
Product Alienbin
Versions
  • Version <= 1.0.0 is affected

References

Problem Types

  • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') CWE