Service crash or code execution via SASL underflow
Published Sep 7, 2026 · Updated Sep 8, 2026
Heap buffer overflow in Red Hat 389 Directory Server allows remote authenticated users to crash the service or execute code via SASL records. sasl_io_start_packet() accepts wrapped-record lengths below the consumed offset, so sasl_io_read_packet() underflows an unsigned subtraction and requests about 4 GiB into a 1024-byte heap buffer. Exploitation requires a successful SASL bind with integrity protection and affects only connections that negotiate a SASL security layer.
Summary
What happened
Heap buffer overflow in Red Hat 389 Directory Server allows remote authenticated users to crash the service or execute code via SASL records. sasl_io_start_packet() accepts wrapped-record lengths below the consumed offset, so sasl_io_read_packet() underflows an unsigned subtraction and requests about 4 GiB into a 1024-byte heap buffer. Exploitation requires a successful SASL bind with integrity protection and affects only connections that negotiate a SASL security layer.
The record
- CVE
- CVE-2026-18355
- Published
- Sep 7, 2026
- Updated
- Sep 8, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
- Classifications
- CWE-191, T1210, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 7, 2026CVE publishedPublication date reported by the CVE source.
- Sep 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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