CVE-2026-127135

MEDIUM
Published Nov 12, 2026 Modified Nov 12, 2026 CWE-96

Description

SOGo before 5.12.13 contains a Sieve script injection vulnerability that allows authenticated users to inject arbitrary Sieve directives by inserting unescaped notification address values into a generated Sieve script. Attackers can embed Sieve redirect or discard statements within the notificationAddress preference to bypass the administrator-configured forwarding-domain constraint and redirect or discard incoming mail.

Is your site exposed to CVE-2026-127135?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

4.3
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Weakness Type (CWE)

CWE-96 CWE-96

References

Frequently Asked Questions

What is CVE-2026-127135? +
SOGo before 5.12.13 contains a Sieve script injection vulnerability that allows authenticated users to inject arbitrary Sieve directives by inserting unescaped notification address values into a generated Sieve script. Attackers can embed Sieve redirect or discard statements within the notificationAddress preference to bypass the administrator-configured forwarding-domain constraint and redirect or discard incoming mail. It has a CVSS v3.1 base score of 4.3 (MEDIUM).
How severe is CVE-2026-127135? +
CVE-2026-127135 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
How do I check if I'm vulnerable to CVE-2026-127135? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-127135 — free, no signup required.

Patch and protect

Block known exploits with a web application firewall while you patch, keep your own devices clean, or test the fix on a fresh server.

Compare VPS prices →

Affiliate links: we may earn a commission, your price stays the same.