CRE-2025-0038

Loki fails to cache entries due to Memcached out-of-memory errorLow

Impact: 5/10

Mitigation: 3/10

CRE-2025-0038View on GitHub

LokiMemcachedCacheMemoryInfrastructureKnown IssuePublic

Description

Grafana Loki may emit errors when attempting to write to a Memcached backend that has run out of available memory. This results in dropped index or query cache entries, which can degrade query performance but does not interrupt ingestion.

Mitigation

- Increase the memory limit allocated to your Memcached deployment. - Use Memcached eviction policies (e.g., LRU) or tune object size limits. - Monitor Memcached memory metrics (e.g., `memcached_mem_bytes`) and set alerts for high usage. - Consider using a more robust backend like Redis for larger or persistent caches.

References

• https://grafana.com/docs/loki/latest/configure/#cache_config
• https://github.com/memcached/memcached/wiki/FAQ#im-getting-out-of-memory-errors