Skip to main content

389 Directory Server CVE-2026-18355

| EUVDEUVD-2026-72455 HIGH
Integer Underflow (CWE-191)
2026-09-07 redhat GHSA-r5vv-79fp-2427
RCE Buffer Overflow Denial Of Service Integer Overflow Red Hat Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Suse Red Hat Directory Server 11 Red Hat Directory Server 12 Red Hat Directory Server 13 Red Hat
7.5
CVSS 3.1 · Vendor: redhat
Share

Severity by source

Vendor (redhat) PRIMARY
7.5 HIGH
AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
7.5 HIGH

Network-reachable LDAP service requires an authenticated SASL bind with SSF > 0 before the vulnerable path is accessible, justifying PR:L and AC:H; heap overflow with attacker-controlled content supports C:H/I:H/A:H.

3.1 AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE
HIGH
qualitative
Red Hat
7.5 HIGH
qualitative

Primary rating from Vendor (redhat).

CVSS VectorVendor: redhat

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Analysis Generated
Sep 07, 2026 - 15:12 vuln.today
CVE Published
Sep 07, 2026 - 14:14 cve.org
HIGH 7.5

DescriptionCVE.org

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.

AnalysisAI

Heap buffer overflow in 389 Directory Server's SASL I/O layer allows a remote authenticated attacker to crash the server or potentially execute arbitrary code. The root cause is an integer underflow in sasl_io_read_packet(): a crafted SASL record with a wire-format length of 0, 1, or 2 bytes causes an unsigned subtraction to wrap around, instructing PR_Recv to read approximately 4 GiB of attacker-controlled network data into a 1024-byte heap buffer. …

Unlock full vulnerability intelligence

  • Risk assessment & exploitation conditions
  • Attack chain visualization
  • Remediation with exact patch versions
  • Threat intelligence from 22 sources
  • Personal watchlist & email alerts
Continue with Google Continue with GitHub

Free forever · No credit card required

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
technique details hidden
Delivery
technique details hidden
Exploit
technique details hidden
Execution
technique details hidden
Persist
technique details hidden
Impact
technique details hidden
Sign in to reveal

Vulnerability AssessmentAI

Exploitation Exploitation requires three concrete preconditions: (1) a valid LDAP bind credential for any user account in the directory, consistent with PR:L - no administrative privilege is needed; (2) the attacker must complete a SASL bind with integrity or privacy protection negotiated (SSF > 0), meaning the SASL mechanism used must support and activate an integrity layer - GSSAPI with Kerberos (the FreeIPA/IdM default), SASL DIGEST-MD5 with integrity, or similar; and (3) network connectivity to the 389-ds LDAP port (default 389/636). … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The Red Hat-assigned CVSS 3.1 vector (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, score 7.5) is consistent with the exploitation conditions: network-accessible, no user interaction required, but gated behind both a valid LDAP credential and an SSF > 0 SASL session (AC:H, PR:L). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation Apply the updated 389-ds-base RPM errata from Red Hat via `dnf update 389-ds-base` once errata are published; monitor https://access.redhat.com/security/cve/CVE-2026-18355 and the associated Bugzilla entry (2509186) for the exact patched package version, which had not been confirmed in available data at time of analysis. … Detailed patch versions, workarounds, and compensating controls in full report.
Sign in to read full assessment

Recommended ActionAI

Within 24 hours, inventory all 389 Directory Server instances in production, including exact versions and network scope. …

Sign in for detailed remediation steps and compensating controls.

Threat intelligence, references, and detailed analysis are available after sign-in.

More in Red Hat Enterprise Linux 10

View all
CVE-2026-18663 MEDIUM
5.9 Aug 12

Heap corruption via double-free in 389-ds-base's LDAP control parsing allows an unauthenticated remote attacker to crash
CVE-2026-4631 CRITICAL POC
9.8 Apr 07

Remote code execution in Cockpit's web interface allows unauthenticated attackers to execute arbitrary commands on the h
CVE-2026-4480 CRITICAL POC
9.0 May 26

Remote code execution in Samba's printing subsystem allows remote attackers to inject arbitrary shell commands via craft
CVE-2026-18922 CRITICAL
9.8 Sep 07

Authentication bypass in 389 Directory Server (shipped as Red Hat Directory Server 11-13 and within RHEL 6-10) lets remo
CVE-2026-14544 CRITICAL
9.8 Jul 03

Remote code execution and privilege escalation in HPLIP (HP Linux Imaging and Printing) affects the hpcups print filter

CVE-2026-76578 CRITICAL
9.8 Sep 07

Unauthenticated privilege escalation in FreeIPA (Red Hat Identity Management) allows a remote attacker to gain genuine a
CVE-2026-5121 HIGH
7.5 Mar 30

Remote code execution in libarchive on 32-bit systems allows unauthenticated attackers to execute arbitrary code via spe
CVE-2026-28369 CRITICAL
9.1 Mar 27

HTTP request smuggling in Undertow (the embedded web server underpinning JBoss EAP, Red Hat Data Grid, and Apache Camel

CVE-2026-28368 CRITICAL
9.1 Mar 27

HTTP request smuggling in Red Hat Undertow allows remote unauthenticated attackers to bypass front-end security controls
CVE-2026-33845 CRITICAL
9.1 Apr 30

Out-of-bounds read in the GnuTLS DTLS handshake reassembly logic lets remote unauthenticated attackers trigger an intege
CVE-2026-28367 CRITICAL
9.1 Mar 27

HTTP request smuggling in Undertow allows remote unauthenticated attackers to send `\r\r\r` as a header block terminator
CVE-2026-16526 HIGH
8.8 Jul 30

Local privilege escalation in Performance Co-Pilot (PCP) on Red Hat Enterprise Linux 6 through 10 and OpenShift Containe

Same weakness CWE-191 – Integer Underflow

View all
CVE-2014-0497 CRITICAL POC
9.8
CVE-2015-5212 MEDIUM
6.8
CVE-2017-14496 HIGH POC
7.5
CVE-2014-8768 MEDIUM POC
5.0
CVE-2017-11757 CRITICAL POC
9.8
CVE-2024-23313 CRITICAL POC
9.8
CVE-2021-3323 CRITICAL POC
9.8
CVE-2021-21811 CRITICAL POC
9.8

Same technique RCE

View all
CVE-2021-44228 CRITICAL POC
10.0
CVE-2017-7269 CRITICAL POC
9.8
CVE-2022-47966 CRITICAL POC
9.8
CVE-2012-4681 CRITICAL POC
9.8
CVE-2023-3519 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2016-4117 CRITICAL POC
9.8
CVE-2015-3113 CRITICAL POC
9.8

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Liberty Linux 8 Fixed
SUSE Linux Enterprise Module for Server Applications 15 SP7 Affected
SUSE Linux Enterprise Server 15 SP7 Affected
SUSE Linux Enterprise Server 16.0 Affected
SUSE Linux Enterprise Server 16.1 Affected

Share

CVE-2026-18355 vulnerability details – vuln.today
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy