CVE-2026-18355

Sažetak

A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), the wrapped-record length read from the wire is validated only against an upper bound. A small wire length (0, 1, or 2) produces an encrypted_buffer_count below the already-consumed encrypted_buffer_offset, causing an unsigned subtraction underflow in sasl_io_read_packet(). PR_Recv is then requested to read approximately 4 GiB into a 1024-byte heap buffer, resulting in a heap buffer overflow with attacker-controlled content. After a successful SASL bind with integrity protection (SSF > 0), a remote authenticated attacker can cause a denial of service or potentially achieve remote code execution. This flaw is distinct from CVE-2026-11774, whose fix only guards against upper-bound overflow.

Reference

CVSS

Base:	7.5
Impact:	5.9
Exploitability:	1.6

Pristup

Vektor	Složenost	Autentikacija
NETWORK	HIGH	LOW

Impact

Povjerljivost	Cjelovitost	Dostupnost
HIGH	HIGH	HIGH

CVSS vektor

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Zadnje važnije ažuriranje

07-09-2026 - 15:17

Objavljeno

07-09-2026 - 15:17