CVE-2026-52681
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.
What this means for your business
- An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 17% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 3.1 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L- Weakness
- CWE-1050
- Assigned by
- security@open-xchange.com
Dates
- Published
- 2026-08-28
- Last modified
- 2026-09-03
- Sources
- NVD