CVE catalog

CVE-2026-18355

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

[CVE catalog]

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Published: Sep 7, 2026, 9:00:00 AM UTC
Updated: Sep 7, 2026, 3:17:30 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.84% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	389-ds-base	sid	`3.3.1-3`	fixed
Debian	389-ds-base	trixie	`3.1.2+dfsg1-1+deb13u1`	vulnerable
Debian	389-ds-base	bookworm	`2.3.1+dfsg1-1+deb12u1`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	389-ds-base	source	sid	`3.3.1-1`	not yet assigned	Not reported	Not reported
Debian	389-ds-base	source	trixie	`(unfixed)`	not yet assigned	Not reported	Not reported
Debian	389-ds-base	source	bookworm	`(unfixed)`	not yet assigned	Not reported	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[389-ds]Affected
Source package: [389-ds-base]
Details (2)
- 2.3.1+dfsg1-1+deb12u1 · all · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
- 2.3.1+dfsg1-1+deb12u1 · all · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
[389-ds-base]Affected
Details (2)
- 2.3.1+dfsg1-1+deb12u1 · amd64 · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
- 2.3.1+dfsg1-1+deb12u1 · arm64 · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
[389-ds-base-dev]Affected
Source package: [389-ds-base]
Details (2)
- 2.3.1+dfsg1-1+deb12u1 · amd64 · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
- 2.3.1+dfsg1-1+deb12u1 · arm64 · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
[389-ds-base-libs]Affected
Source package: [389-ds-base]
Details (2)
- 2.3.1+dfsg1-1+deb12u1 · amd64 · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
- 2.3.1+dfsg1-1+deb12u1 · arm64 · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
[cockpit-389-ds]Affected
Source package: [389-ds-base]
Details (2)
- 2.3.1+dfsg1-1+deb12u1 · all · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
- 2.3.1+dfsg1-1+deb12u1 · all · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
[python3-lib389]Affected
Source package: [389-ds-base]
Details (2)
- 2.3.1+dfsg1-1+deb12u1 · all · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12
- 2.3.1+dfsg1-1+deb12u1 · all · bookworm
  Affected
  nvd · 389-ds-base · debian · bookworm; nvd · 389-ds-base · debian · 12

[Debian 13 (Trixie)]

[389-ds]Affected
Source package: [389-ds-base]
Details (2)
- 3.1.2+dfsg1-1+deb13u1 · all · trixie
  Affected
  nvd · 389-ds-base · debian · 13
- 3.1.2+dfsg1-1+deb13u1 · all · trixie
  Affected
  nvd · 389-ds-base · debian · 13
[389-ds-base]Affected
Details (2)
- 3.1.2+dfsg1-1+deb13u1 · amd64 · trixie
  Affected
  nvd · 389-ds-base · debian · 13
- 3.1.2+dfsg1-1+deb13u1 · arm64 · trixie
  Affected
  nvd · 389-ds-base · debian · 13
[389-ds-base-dev]Affected
Source package: [389-ds-base]
Details (2)
- 3.1.2+dfsg1-1+deb13u1 · amd64 · trixie
  Affected
  nvd · 389-ds-base · debian · 13
- 3.1.2+dfsg1-1+deb13u1 · arm64 · trixie
  Affected
  nvd · 389-ds-base · debian · 13
[389-ds-base-libs]Affected
Source package: [389-ds-base]
Details (2)
- 3.1.2+dfsg1-1+deb13u1 · amd64 · trixie
  Affected
  nvd · 389-ds-base · debian · 13
- 3.1.2+dfsg1-1+deb13u1 · arm64 · trixie
  Affected
  nvd · 389-ds-base · debian · 13
[cockpit-389-ds]Affected
Source package: [389-ds-base]
Details (2)
- 3.1.2+dfsg1-1+deb13u1 · all · trixie
  Affected
  nvd · 389-ds-base · debian · 13
- 3.1.2+dfsg1-1+deb13u1 · all · trixie
  Affected
  nvd · 389-ds-base · debian · 13
[python3-lib389]Affected
Source package: [389-ds-base]
Details (2)
- 3.1.2+dfsg1-1+deb13u1 · all · trixie
  Affected
  nvd · 389-ds-base · debian · 13
- 3.1.2+dfsg1-1+deb13u1 · all · trixie
  Affected
  nvd · 389-ds-base · debian · 13

Observed: Oct 23, 2026, 9:29:13 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]