Is there a public exploit for CVE-2026-18355?

No public exploit for CVE-2026-18355 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-18355?

CVE-2026-18355 scores CVSS 7.5 (v3.1), rated high. EPSS puts the chance of exploitation in the next 30 days at 0.84%.

What does CVE-2026-18355 affect?

CVE-2026-18355 affects Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service, Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions, Red Hat Directory Server 11.7 E4S for RHEL 8, Red Hat Enterprise Linux 9.6 Extended Update Support, Red Hat Directory Server 12.2 E4S for RHEL 9, Red Hat Enterprise Linux 8.

7.5 High

A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base).

CVE-2026-18355

A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasliostartpacket(), 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 encryptedbuffercount below the already-consumed encryptedbufferoffset, causing an unsigned subtraction underflow in saslioreadpacket(). PRRecv 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.

Assessment

CVSS: 7.5 (v3.1)
Severity: High
EPSS: 0.84% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 7 September 2026
Last updated: 4 November 2026
Affected: Red Hat · Red Hat Directory Server 11.5 E4S for RHEL 8 · Red Hat Directory Server 11.7 E4S for RHEL 8 · Red Hat Directory Server 11.9 for RHEL 8 · Red Hat Directory Server 12.2 E4S for RHEL 9
Assigner: redhat

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

At the source

EUVD (ENISA)

References

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