Описание
An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.
Отчет
Red Hat rates this issue as Important. After a successful SASL bind with integrity protection, an authenticated attacker can send a SASL-framed packet whose length prefix wraps when processed in sasl_io_start_packet(), bypassing nsslapd-maxsasliosize and causing a heap buffer overflow of up to approximately two megabytes of attacker-controlled data. This flaw is independent of CVE-2025-14905 (schema.c). Any domain user with a Kerberos ticket can trigger it remotely after GSSAPI authentication. Red Hat assigns C:L/I:L rather than Critical because remote code execution on current platforms with glibc 2.32+ is blocked by tcache safe linking; RCE was demonstrated on RHEL 8 with glibc 2.28 but required a heap address leak. Denial of service is reliable on all platforms.
Меры по смягчению последствий
No complete workaround exists; nsslapd-maxsasliosize is bypassed by the integer overflow. Mitigations that reduce exposure: restrict SASL mechanisms (disable DIGEST-MD5 if not required; GSSAPI cannot be disabled in FreeIPA/IdM without breaking Kerberos authentication); firewall LDAP ports (389/636) to trusted networks; monitor for SASL-framed packets with length prefix 0xFFFFFFFC through 0xFFFFFFFF; enable audit logging (nsslapd-auditlog-logging-enabled: on); on RHEL 8, upgrading glibc reduces RCE exploitability but does not eliminate DoS.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Directory Server 12 | redhat-ds:12/389-ds-base | Affected | ||
| Red Hat Directory Server 13 | 389-ds-base | Not affected | ||
| Red Hat Enterprise Linux 6 | 389-ds-base | Not affected | ||
| Red Hat Directory Server 11.5 E4S for RHEL 8 | redhat-ds | Fixed | RHSA-2026:36204 | 07.07.2026 |
| Red Hat Directory Server 11.7 E4S for RHEL 8 | redhat-ds | Fixed | RHSA-2026:36208 | 07.07.2026 |
| Red Hat Directory Server 11.9 for RHEL 8 | redhat-ds | Fixed | RHSA-2026:36200 | 07.07.2026 |
| Red Hat Directory Server 12.2 E4S for RHEL 9 | redhat-ds | Fixed | RHSA-2026:36641 | 08.07.2026 |
| Red Hat Directory Server 12.4 E4S for RHEL 9 | redhat-ds | Fixed | RHSA-2026:36209 | 07.07.2026 |
| Red Hat Enterprise Linux 10 | 389-ds-base | Fixed | RHSA-2026:36196 | 07.07.2026 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | 389-ds-base | Fixed | RHSA-2026:36670 | 08.07.2026 |
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Дополнительная информация
Статус:
EPSS
7.6 High
CVSS3
Связанные уязвимости
An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.
An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.
An integer overflow flaw was found in the SASL I/O layer of 389 Direct ...
An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.
EPSS
7.6 High
CVSS3