Samba: infinite loop in mdssvc rpc service for spotlight (CVE-2023-34966)
Published Last modified Sources: Debian, CVE.org, BSI
What is affected, what to do
An infinite loop vulnerability was found in Samba's mdssvc RPC service for Spotlight. When parsing Spotlight mdssvc RPC packets sent by the client, the core unmarshalling function sl_unpack_loop() did not validate a field in the network packet that contains the count of elements in an array-like structure.
Update Red Hat Enterprise Linux 8 to version 0:4.18.6-1.el8, Red Hat Enterprise Linux 8.6 Extended Update Support to version 0:4.15.5-15.el8_6, Red Hat Enterprise Linux 8.8 Extended Update Support to version 0:4.17.5-5.el8_8.
- Affected
- Red Hat Enterprise Linux 8
lt *..0:4.18.6-1.el8 - Red Hat Enterprise Linux 8.6 Extended Update Support
lt *..0:4.15.5-15.el8_6 - Red Hat Enterprise Linux 8.8 Extended Update Support
lt *..0:4.17.5-5.el8_8 - Red Hat Enterprise Linux 9
lt *..0:4.18.6-100.el9 - Red Hat Enterprise Linux 9.2 Extended Update Support
lt *..0:4.17.5-105.el9_2 - Red Hat Virtualization 4 for Red Hat Enterprise Linux 8
lt *..0:4.15.5-15.el8_6
- Red Hat Enterprise Linux 8
- Fixed in
- Red Hat Enterprise Linux 8
0:4.18.6-1.el8 - Red Hat Enterprise Linux 8.6 Extended Update Support
0:4.15.5-15.el8_6 - Red Hat Enterprise Linux 8.8 Extended Update Support
0:4.17.5-5.el8_8 - Red Hat Enterprise Linux 9
0:4.18.6-100.el9 - Red Hat Enterprise Linux 9.2 Extended Update Support
0:4.17.5-105.el9_2 - Red Hat Virtualization 4 for Red Hat Enterprise Linux 8
0:4.15.5-15.el8_6
- Red Hat Enterprise Linux 8
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Metrics
7.5
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
7.5
CVSS v3
Severity High on the scale from 0 to 10.
Source: Debian, CVE.org, BSI
62.3 %
EPSS score
High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
Source: FIRST EPSS, percentile 99.19
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 119.23 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.5 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.5
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 62.3 %
- High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 99.19
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-835
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
An infinite loop vulnerability was found in Samba's mdssvc RPC service for Spotlight. When parsing Spotlight mdssvc RPC packets sent by the client, the core unmarshalling function sl_unpack_loop() did not validate a field in the network packet that contains the count of elements in an array-like structure. By passing 0 as the count value, the attacked function will run in an endless loop consuming 100% CPU. This flaw allows an attacker to issue a malformed RPC request, triggering an infinite loop, resulting in a denial of service condition.
Source: Debian Security Advisories, cvelistv5, NVD (NIST), BSI CSAF, BSI WID Portal
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 6 |
|
|
| Red Hat | Red Hat Enterprise Linux 7 |
|
|
| Red Hat | Red Hat Enterprise Linux 8 |
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support |
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Extended Update Support |
|
|
| Red Hat | Red Hat Enterprise Linux 9 |
|
|
| Red Hat | Red Hat Enterprise Linux 9.2 Extended Update Support |
|
|
| Red Hat | Red Hat Storage 3 |
|
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| Red Hat | Red Hat Virtualization 4 for Red Hat Enterprise Linux 8 |
|
|
| samba | samba |
|
|
| Avaya | Aura Application Enablement Services |
|
|
| Avaya | Aura Experience Portal |
|
|
| Avaya | CMS |
|
|
| HPE | HP-UX (CIFS) Client/Server |
|
|
| IBM | QRadar SIEM |
|
|
| Open Source | Samba |
|
|
| Ubuntu | Linux |
|
|
Vendors and products
- Avaya Aura Application Enablement Services
- Avaya Aura Experience Portal
- Avaya CMS
- Debian Debian Linux
- Debian Samba
- Fedora Project Infrastructure Fedora
- Hewlett Packard Enterprise (HPE) Hp-ux (cifs) Client/server
- IBM Qradar Siem
- Open Source Samba
- Red Hat Red Hat Enterprise Linux 6
- Red Hat Red Hat Enterprise Linux 7
- Red Hat Red Hat Enterprise Linux 8
Affected operating systems
| Linux | debian | debian_linux | 11.0 |
| Linux | debian | debian_linux | 12.0 |
| Linux | redhat | enterprise_linux | 8.0 |
| Linux | redhat | enterprise_linux | 9.0 |
| Linux | debian | samba | bookworm |
| Linux | debian | samba | bullseye |
| Other | fedoraproject | fedora | 37 |
| Other | fedoraproject | fedora | 38 |
Weakness classes (CWE)
CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
Base
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
Entry at MITRE CWE-835
References & sources
- access.redhat.comRHSA-2023:6667Vendor advisory, x_refsource_REDHAT, Third-party advisory
- access.redhat.comRHSA-2023:7139Vendor advisory, x_refsource_REDHAT, Third-party advisory
- access.redhat.comRHSA-2024:0423Vendor advisory, x_refsource_REDHAT
- access.redhat.comRHSA-2024:0580Vendor advisory, x_refsource_REDHAT
- access.redhat.comRHSA-2024:4101Vendor advisory, x_refsource_REDHAT
- access.redhat.comsecurity/cve/CVE-2023-34966Vulnerability database, x_refsource_REDHAT, Third-party advisory
- bugzilla.redhat.comRHBZ#2222793Issue tracking, x_refsource_REDHAT, Issue tracking, Third-party advisory
- samba.orgsamba/security/CVE-2023-34966Vendor advisory
- lists.fedoraproject.orgarchives/list/package-announce@lists.fedoraproject.org/message/…x_transferred
- lists.fedoraproject.orgarchives/list/package-announce@lists.fedoraproject.org/message/…x_transferred
- security.netapp.comadvisory/ntap-20230731-0010x_transferred
- debian.orgsecurity/2023/dsa-5477x_transferred
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedRed Hat
Show 22 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2023/34xxx/CVE-2023-34966.json">CVE-2023-34966</a>Reference added —https://access.redhat.com/errata/RHSA-2023:6667Reference added —https://access.redhat.com/errata/RHSA-2023:7139Reference added —https://access.redhat.com/errata/RHSA-2024:0423Reference added —https://access.redhat.com/errata/RHSA-2024:0580Reference added —https://access.redhat.com/errata/RHSA-2024:4101Reference added —https://access.redhat.com/security/cve/CVE-2023-34966Reference added —https://bugzilla.redhat.com/show_bug.cgi?id=2222793Reference added —https://www.samba.org/samba/security/CVE-2023-34966Reference removed https://access.redhat.com/errata/RHSA-2023:6667—Reference removed https://access.redhat.com/errata/RHSA-2023:7139—Reference removed https://access.redhat.com/errata/RHSA-2024:0423—Reference removed https://access.redhat.com/errata/RHSA-2024:0580—Reference removed https://access.redhat.com/errata/RHSA-2024:4101—Reference removed https://access.redhat.com/security/cve/CVE-2023-34966—Reference removed https://bugzilla.redhat.com/show_bug.cgi?id=2222793—Reference removed https://www.samba.org/samba/security/CVE-2023-34966—Reference type removed https://access.redhat.com/errata/RHSA-2023:6667 Types: Third Party Advisory—Reference type removed https://access.redhat.com/errata/RHSA-2023:7139 Types: Third Party Advisory—Reference type removed https://access.redhat.com/security/cve/CVE-2023-34966 Types: Third Party Advisory—Reference type removed https://bugzilla.redhat.com/show_bug.cgi?id=2222793 Types: Issue Tracking, Third Party Advisory—Reference type removed https://www.samba.org/samba/security/CVE-2023-34966 Types: Vendor Advisory—Source identifier: secalert@redhat.com
Record modifiedCVE Program
Show 29 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —https://access.redhat.com/errata/RHSA-2023:6667Reference added —https://access.redhat.com/errata/RHSA-2023:7139Reference added —https://access.redhat.com/errata/RHSA-2024:0423Reference added —https://access.redhat.com/errata/RHSA-2024:0580Reference added —https://access.redhat.com/errata/RHSA-2024:4101Reference added —https://access.redhat.com/security/cve/CVE-2023-34966Reference added —https://bugzilla.redhat.com/show_bug.cgi?id=2222793Reference added —https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BPCSGND7LO467AJGR5DYBGZLTCGTOBCC/Reference added —https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OT74M42E6C36W7PQVY3OS4ZM7DVYB64Z/Reference added —https://security.netapp.com/advisory/ntap-20230731-0010/Reference added —https://www.debian.org/security/2023/dsa-5477Reference added —https://www.samba.org/samba/security/CVE-2023-34966Reference removed https://access.redhat.com/errata/RHSA-2023:6667—Reference removed https://access.redhat.com/errata/RHSA-2023:7139—Reference removed https://access.redhat.com/errata/RHSA-2024:0423—Reference removed https://access.redhat.com/errata/RHSA-2024:0580—Reference removed https://access.redhat.com/errata/RHSA-2024:4101—Reference removed https://access.redhat.com/security/cve/CVE-2023-34966—Reference removed https://bugzilla.redhat.com/show_bug.cgi?id=2222793—Reference removed https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BPCSGND7LO467AJGR5DYBGZLTCGTOBCC/—Reference removed https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OT74M42E6C36W7PQVY3OS4ZM7DVYB64Z/—Reference removed https://security.netapp.com/advisory/ntap-20230731-0010/—Reference removed https://www.debian.org/security/2023/dsa-5477—Reference removed https://www.samba.org/samba/security/CVE-2023-34966—Reference type removed https://access.redhat.com/errata/RHSA-2023:6667 Types: Third Party Advisory—Reference type removed https://access.redhat.com/errata/RHSA-2023:7139 Types: Third Party Advisory—Reference type removed https://access.redhat.com/security/cve/CVE-2023-34966 Types: Third Party Advisory—Reference type removed https://bugzilla.redhat.com/show_bug.cgi?id=2222793 Types: Issue Tracking, Third Party Advisory—Reference type removed https://www.samba.org/samba/security/CVE-2023-34966 Types: Vendor Advisory—Source identifier: af854a3a-2127-422b-91ae-364da2661108
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