Описание
An attacker that has 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.
A flaw was found in Dovecot. An authenticated attacker can use a Sieve script with the editheader extension to trigger a use-after-free vulnerability in the mail editing code. This can lead to memory corruption, potentially crashing the mail delivery process and allowing for arbitrary code execution in the context of that process.
Отчет
This flaw requires an attacker to authenticate with valid credentials before it can be exploited, and exploitation additionally depends on the Sieve editheader extension being enabled, which is not Dovecot's default configuration. Because the CVSS attack vector requires low-privileged authentication (PR:L) rather than unauthenticated remote access, and the confirmed impact is primarily memory corruption leading to a crash of the mail delivery process, this issue is rated Important rather than Critical. Disabling the Sieve editheader extension fully mitigates the vulnerability without requiring a package update.
Меры по смягчению последствий
To mitigate this vulnerability, disable the Sieve editheader extension in the Dovecot configuration. After modifying the configuration, the Dovecot service must be restarted for the changes to take effect. Disabling this extension will remove its associated functionality.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | dovecot | Out of support scope | ||
| Red Hat Enterprise Linux 7 | dovecot | Affected | ||
| Red Hat Enterprise Linux 10 | dovecot | Fixed | RHSA-2026:79371 | 08.10.2026 |
| Red Hat Enterprise Linux 8 | dovecot | Fixed | RHSA-2026:76763 | 06.10.2026 |
| Red Hat Enterprise Linux 9 | dovecot | Fixed | RHSA-2026:80825 | 12.10.2026 |
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Дополнительная информация
Статус:
9.1 Critical
CVSS3
Связанные уязвимости
An attacker that has 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.
An attacker that has 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.
An attacker that has valid credentials can use a Sieve script with the ...
An attacker that has 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.
9.1 Critical
CVSS3