(389-ds-base). After a successful SASL bind with integrity protection (SSF > 0),
an authenticated attacker can send a specially crafted oversized LDAP UNBIND packet
that is copied into a 512-byte heap receive buffer without a bounds check in
sasl_io_recv() in sasl_io.c. This allows up to approximately 2 megabytes of
attacker-controlled data to overflow the buffer, causing a denial of service (server
crash). In FreeIPA and Red Hat Identity Management deployments, any domain user with
a valid Kerberos ticket, any enrolled host, or any service account can trigger this
vulnerability over the network after authenticating via GSSAPI.
The vulnerable code path has existed since approximately 2013 (389-ds-base 1.3.2) and
was not addressed by the CVE-2025-14905 fix, which patched a separate heap overflow
in schema.c only.
Analysis and contextual insights are available on OpenCVE Cloud.
Vendor Workaround
There is no complete workaround for this flaw. Mitigations that reduce exposure: 1. Restrict network access to LDAP ports (389/636) to trusted networks only. Note: In FreeIPA/IdM deployments, enrolled clients require LDAP access and this may not be practical. 2. If DIGEST-MD5 is not required, disable it via nsslapd-allowed-sasl-mechanisms in cn=config. GSSAPI/Kerberos cannot be disabled in FreeIPA/IdM without breaking domain authentication. 3. Monitor for oversized LDAP UNBIND packets (standard UNBIND is 7 bytes; alert on UNBIND packets exceeding ~100 bytes). 4. Lowering nsslapd-maxbersize reduces maximum overflow size but does not eliminate the vulnerability.
Tracking
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No advisories yet.
Tue, 07 Jul 2026 14:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat rhel Aus
Redhat rhel Els Redhat rhel Eus Long Life |
|
| CPEs | cpe:/o:redhat:enterprise_linux:8 |
cpe:/a:redhat:enterprise_linux:8::appstream cpe:/a:redhat:rhel_aus:8.4::appstream cpe:/a:redhat:rhel_aus:8.6::appstream cpe:/a:redhat:rhel_eus_long_life:8.4::appstream cpe:/a:redhat:rhel_eus_long_life:8.6::appstream cpe:/o:redhat:rhel_els:7 |
| Vendors & Products |
Redhat rhel Aus
Redhat rhel Els Redhat rhel Eus Long Life |
|
| References |
|
Tue, 07 Jul 2026 13:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat directory Server E4s
Redhat rhel E4s Redhat rhel Tus |
|
| CPEs | cpe:/a:redhat:directory_server_e4s:11.5::el8 cpe:/a:redhat:directory_server_e4s:11.7::el8 cpe:/a:redhat:rhel_e4s:8.8::appstream cpe:/a:redhat:rhel_e4s:9.4::appstream cpe:/a:redhat:rhel_tus:8.8::appstream |
|
| Vendors & Products |
Redhat directory Server E4s
Redhat rhel E4s Redhat rhel Tus |
|
| References |
|
Tue, 07 Jul 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
threat_severity
|
Tue, 07 Jul 2026 10:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). After a successful SASL bind with integrity protection (SSF > 0), an authenticated attacker can send a specially crafted oversized LDAP UNBIND packet that is copied into a 512-byte heap receive buffer without a bounds check in sasl_io_recv() in sasl_io.c. This allows up to approximately 2 megabytes of attacker-controlled data to overflow the buffer, causing a denial of service (server crash). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, any enrolled host, or any service account can trigger this vulnerability over the network after authenticating via GSSAPI. The vulnerable code path has existed since approximately 2013 (389-ds-base 1.3.2) and was not addressed by the CVE-2025-14905 fix, which patched a separate heap overflow in schema.c only. | |
| Title | 389-ds-base: 389-ds-base: heap buffer overflow in sasl_io_recv() via padded sasl unbind | |
| First Time appeared |
Redhat
Redhat directory Server Redhat enterprise Linux |
|
| Weaknesses | CWE-122 | |
| CPEs | cpe:/a:redhat:directory_server:11 cpe:/a:redhat:directory_server:12 cpe:/a:redhat:directory_server:13 cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:enterprise_linux:7 cpe:/o:redhat:enterprise_linux:8 cpe:/o:redhat:enterprise_linux:9 |
|
| Vendors & Products |
Redhat
Redhat directory Server Redhat enterprise Linux |
|
| References |
| |
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: redhat
Published:
Updated: 2026-07-07T13:42:40.612Z
Reserved: 2026-06-08T16:13:02.502Z
Link: CVE-2026-11610
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