CVE-2026-52681

LowCVSS 3.1

Published: 28/08/2026(UTC)Updated: 28/08/2026(UTC)Translated: 28/08/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.25%

17th percentile - higher than 17% of all known CVEs

Summary

Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the accounting by repeatedly changing the active script. Compiled script files are also not removed when a script is deleted or renamed. The configured Sieve CPU limit can be bypassed, allowing sustained CPU consumption, and the leftover files increase disk consumption. Both can cause degradation of service for mail delivery. Monitor system for abnormal CPU usage and disk consumption. Update to non-vulnerable version. No publicly available exploits are known.

Risk Assessment

The risk includes degradation of mail service due to excessive CPU and disk usage, which could lead to disruptions in mail delivery.

Recommendation

It is recommended to update to a non-vulnerable version and monitor the system for anomalies in CPU and disk usage.

Other vulnerabilities in Sieve

CVE-2026-42007Critical
An attacker with valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available exploits are known.

Original NVD description (English source)