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CVE-2026-40203

Open-Xchange GmbH / OX Dovecot Pro PUBLISHED

Description (CNA)

When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.

Affected (CNA)

Vendor / productVersions
Open-Xchange GmbH / OX Dovecot Proaffected 2.3.0 before 2.3.22.2; affected 3.0.0 before 3.0.7; affected 3.1.0 before 3.1.6
Open-Xchange GmbH / OX Dovecot CEaffected 2.3.0 before 2.4.5

CWE

CWE-200

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.