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NVD / CVE Program· CNA redhat

CVE-2026-18355: 389-ds-base: 389-ds-base: heap buffer overflow via sasl wrapped-record length lower-bound underflow in sasl_io_start_packet()

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.83% (FIRST EPSS); higher than 57.9% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: 389-ds-base (AlmaLinux:10) 3.2.0-10.el10_2; 389-ds-base-bdb (AlmaLinux:10) 3.2.0-10.el10_2; 389-ds-base-devel (AlmaLinux:10) 3.2.0-10.el10_2.

Low priority for now. Upgrade to 389-ds-base (AlmaLinux:10) 3.2.0-10.el10_2; 389-ds-base-bdb (AlmaLinux:10) 3.2.0-10.el10_2; 389-ds-base-devel (AlmaLinux:10) 3.2.0-10.el10_2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Sep 7, 2026
Updated
Nov 4, 2026
EPSS
0.8% · 57th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat Directory Server 11.5 E4S for RHEL 8

    • 8060020260908152739.0ca98e7e and laternot affected · rpm

  • Red Hat Red Hat Directory Server 11.7 E4S for RHEL 8

    • 8080020260903102346.f969626e and laternot affected · rpm

  • Red Hat Red Hat Directory Server 11.9 for RHEL 8

    • 8100020260904171440.37ed7c03 and laternot affected · rpm

  • Red Hat Red Hat Directory Server 12

    • all versionsaffected

  • Red Hat Red Hat Directory Server 12.2 E4S for RHEL 9

    • 9020020260903155914.1674d574 and laternot affected · rpm

  • Red Hat Red Hat Directory Server 12.4 E4S for RHEL 9

    • 9040020260903102623.1674d574 and laternot affected · rpm

  • Red Hat Red Hat Directory Server 13

    • all versionsunknown

  • Red Hat Red Hat Directory Server 13.2

    • 1788851765 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 10

    • 0:3.2.0-10.el10_2 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support

    • 0:3.0.6-21.el10_0 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 6

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support

    • 0:1.3.11.1-15.el7_9 and laternot affected · rpm

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10389-ds-basebefore 3.2.0-10.el10_23.2.0-10.el10_2
AlmaLinux:10389-ds-base-bdbbefore 3.2.0-10.el10_23.2.0-10.el10_2
AlmaLinux:10389-ds-base-develbefore 3.2.0-10.el10_23.2.0-10.el10_2
AlmaLinux:10389-ds-base-libsbefore 3.2.0-10.el10_23.2.0-10.el10_2
AlmaLinux:10389-ds-base-snmpbefore 3.2.0-10.el10_23.2.0-10.el10_2
AlmaLinux:10python3-lib389before 3.2.0-10.el10_23.2.0-10.el10_2
AlmaLinux:8389-ds-basebefore 1.4.3.39-28.module_el8.10.0+4274+00f9a3f11.4.3.39-28.module_el8.10.0+4274+00f9a3f1
AlmaLinux:8389-ds-base-develbefore 1.4.3.39-28.module_el8.10.0+4274+00f9a3f11.4.3.39-28.module_el8.10.0+4274+00f9a3f1
AlmaLinux:8389-ds-base-legacy-toolsbefore 1.4.3.39-28.module_el8.10.0+4274+00f9a3f11.4.3.39-28.module_el8.10.0+4274+00f9a3f1
AlmaLinux:8389-ds-base-libsbefore 1.4.3.39-28.module_el8.10.0+4274+00f9a3f11.4.3.39-28.module_el8.10.0+4274+00f9a3f1
AlmaLinux:8389-ds-base-snmpbefore 1.4.3.39-28.module_el8.10.0+4274+00f9a3f11.4.3.39-28.module_el8.10.0+4274+00f9a3f1
AlmaLinux:8python3-lib389before 1.4.3.39-28.module_el8.10.0+4274+00f9a3f11.4.3.39-28.module_el8.10.0+4274+00f9a3f1
AlmaLinux:9389-ds-basebefore 2.8.0-10.el9_82.8.0-10.el9_8
AlmaLinux:9389-ds-base-develbefore 2.8.0-10.el9_82.8.0-10.el9_8
AlmaLinux:9389-ds-base-libsbefore 2.8.0-10.el9_82.8.0-10.el9_8
AlmaLinux:9389-ds-base-snmpbefore 2.8.0-10.el9_82.8.0-10.el9_8
AlmaLinux:9python3-lib389before 2.8.0-10.el9_82.8.0-10.el9_8
Debian:12389-ds-basefrom 0—
openSUSE:Leap 16.0389-dsbefore 3.0.7~git2.2846d5288-160000.1.13.0.7~git2.2846d5288-160000.1.1
openSUSE:Tumbleweed389-dsbefore 3.3.1+8c2711bd6-1.13.3.1+8c2711bd6-1.1
Red Hat:directory_server_e4s:11.5::el8389-ds-basebefore 0:1.4.3.34-9.module+el8dsrv+24847+c94540a60:1.4.3.34-9.module+el8dsrv+24847+c94540a6
Red Hat:directory_server_e4s:11.5::el8389-ds-base-debuginfobefore 0:1.4.3.34-9.module+el8dsrv+24847+c94540a60:1.4.3.34-9.module+el8dsrv+24847+c94540a6
Red Hat:directory_server_e4s:11.5::el8389-ds-base-debugsourcebefore 0:1.4.3.34-9.module+el8dsrv+24847+c94540a60:1.4.3.34-9.module+el8dsrv+24847+c94540a6
Red Hat:directory_server_e4s:11.5::el8389-ds-base-develbefore 0:1.4.3.34-9.module+el8dsrv+24847+c94540a60:1.4.3.34-9.module+el8dsrv+24847+c94540a6

+96

Same product

red hat: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-18922389-ds-base: 389-ds-base: sasl plain authentication allows privilege escalation to directory manager via stale identity in cyrus sasl auxiliary property
    39Monitor
  • CVE-2026-19843389-ds-base: 389-ds-base: command injection via unescaped ldap dn in cockpit 389 console ldap editor
    33Monitor
  • CVE-2026-18453389-ds-base: 389-ds-base: pre-authentication null pointer dereference via paged results and use_one_backend control in op_shared_search
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-76560Sep 7, 2026 · 389-ds-base: 389-ds: anonymous ldap client can defeat selfdn aci bind-rule checks via empty bind dn
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:389-ds-base2.8.0-10.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:389-ds-base-bdb3.2.0-10.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:389-ds-base-devel2.8.0-10.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:389-ds-base-legacy-tools1.4.3.39-28.module_el8.10.0+4274+00f9a3f1 · AlmaLinux:8Package registry (OSV)
almalinux:389-ds-base-libs2.8.0-10.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:389-ds-base-snmp2.8.0-10.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:python3-lib3892.8.0-10.el9_8 · AlmaLinux:9Package registry (OSV)
opensuse:389-ds3.3.1+8c2711bd6-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:389-ds-base0:1.3.11.1-15.el7_9 · Red Hat:rhel_els:7Package registry (OSV)
red hat:389-ds-base-debuginfo0:1.3.11.1-15.el7_9 · Red Hat:rhel_els:7Package registry (OSV)
red hat:389-ds-base-debugsource0:1.4.3.35-21.module+el8.8.0+24788+bed99f90 · Red Hat:rhel_e4s:8.8::appstreamPackage registry (OSV)
red hat:389-ds-base-devel0:1.3.11.1-15.el7_9 · Red Hat:rhel_els:7Package registry (OSV)
red hat:389-ds-base-legacy-tools0:1.4.3.35-21.module+el8.8.0+24788+bed99f90 · Red Hat:rhel_e4s:8.8::appstreamPackage registry (OSV)
red hat:389-ds-base-legacy-tools-debuginfo0:1.4.3.35-21.module+el8.8.0+24788+bed99f90 · Red Hat:rhel_e4s:8.8::appstreamPackage registry (OSV)
red hat:389-ds-base-libs0:1.3.11.1-15.el7_9 · Red Hat:rhel_els:7Package registry (OSV)
red hat:389-ds-base-libs-debuginfo0:1.4.3.35-21.module+el8.8.0+24788+bed99f90 · Red Hat:rhel_e4s:8.8::appstreamPackage registry (OSV)
red hat:389-ds-base-snmp0:1.3.11.1-15.el7_9 · Red Hat:rhel_els:7Package registry (OSV)
red hat:389-ds-base-snmp-debuginfo0:1.4.3.35-21.module+el8.8.0+24788+bed99f90 · Red Hat:rhel_e4s:8.8::appstreamPackage registry (OSV)
red hat:cockpit-389-ds0:2.2.7-18.module+el9dsrv+24814+6d9b6eb5 · Red Hat:directory_server_e4s:12.2::el9Package registry (OSV)
red hat:python3-lib3890:1.4.3.35-21.module+el8.8.0+24788+bed99f90 · Red Hat:rhel_e4s:8.8::appstreamPackage registry (OSV)
rocky linux:389-ds-base0:2.8.0-10.el9_8 · Rocky Linux:9Package registry (OSV)
suse:389-ds2.8.2~git10.030ada7a6-150700.3.25.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP7Package registry (OSV)
suse:389-ds3.0.7~git2.2846d5288-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

—

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-189220 days apart389-ds-base: 389-ds-base: sasl plain authentication allows privilege escalation to directory manager via stale identity in cyrus sasl auxiliary property
    39Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-191 · Integer Underflow (Wrap or Wraparound)

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (18 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records