Bug 2529452

Summary:	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() [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Samuele Negrini <snegrini>
Component:	389-ds-base	Assignee:	Viktor Ashirov <vashirov>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	abokovoy, jachapma, mreynolds, spichugi, tbordaz, vashirov
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---	Flags:	fedora-admin-xmlrpc: mirror+
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["940206b2-3924-44de-ba5c-bceb65a4ad83"]}
Fixed In Version:	389-ds-base-3.3.1-3.fc45 389-ds-base-3.1.5-4.fc43 389-ds-base-3.2.3-5.fc44	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-09-25 00:17:09 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2509186

Description Samuele Negrini 2026-09-07 13:16:33 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), the 4-byte wrapped-record length read from the wire is validated only against an upper bound (the check added for CVE-2026-11774). When a SASL-authenticated attacker sends a wrapped record with a wire length of 0 (or 1 or 2), the resulting encrypted_buffer_count (4, 5, or 6 after adding sizeof(uint32_t)) is less than encrypted_buffer_offset (7, the header bytes already consumed). The unsigned subtraction in sasl_io_read_packet() then underflows to approximately 0xFFFFFFFD, and PR_Recv is requested to read roughly 4 GiB into the 1024-byte encrypted_buffer allocated in sasl_io_init_buffers(). This causes a heap buffer overflow with attacker-controlled length and content. The vulnerability requires authentication via a SASL bind with integrity protection (SSF > 0). This is a distinct defect from CVE-2026-11774, which only guards against lengths near UINT32_MAX; the lower-end case is not covered and the vulnerability persists at HEAD.

Comment 1 Viktor Ashirov 2026-09-07 18:39:50 UTC

Fixed in https://github.com/389ds/389-ds-base/commit/82476f968

Comment 2 Fedora Update System 2026-09-07 21:24:41 UTC

FEDORA-2026-b16c9cbc0f (389-ds-base-3.2.3-2.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

Comment 3 Fedora Update System 2026-09-08 01:38:46 UTC

FEDORA-2026-c1e25a4642 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-c1e25a4642`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-c1e25a4642

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 4 Fedora Update System 2026-09-08 01:58:38 UTC

FEDORA-2026-b16c9cbc0f has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b16c9cbc0f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2026-09-08 02:21:03 UTC

FEDORA-2026-0b8bc362b1 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-0b8bc362b1`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-0b8bc362b1

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 6 Fedora Update System 2026-09-09 05:04:39 UTC

FEDORA-2026-b16c9cbc0f has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b16c9cbc0f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 7 Fedora Update System 2026-09-10 01:46:48 UTC

FEDORA-2026-b16c9cbc0f has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b16c9cbc0f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 8 Fedora Update System 2026-09-10 02:07:08 UTC

FEDORA-2026-0b8bc362b1 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-0b8bc362b1`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-0b8bc362b1

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 9 Fedora Update System 2026-09-10 02:16:52 UTC

FEDORA-2026-c1e25a4642 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-c1e25a4642`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-c1e25a4642

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 10 Fedora Update System 2026-09-25 00:17:09 UTC

FEDORA-2026-c1e25a4642 (389-ds-base-3.3.1-3.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 11 Fedora Update System 2026-09-25 00:55:43 UTC

FEDORA-2026-0b8bc362b1 (389-ds-base-3.1.5-4.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 12 Fedora Update System 2026-09-25 01:12:44 UTC

FEDORA-2026-b16c9cbc0f (389-ds-base-3.2.3-5.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.