Red Hat Enterprise Linux 8: Loop with Unreachable Exit Condition
CVE-2023-34966 is a high-severity loop with unreachable exit condition vulnerability in Red Hat Enterprise Linux 8 from Red Hat, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 62.4% chance of exploitation within 30 days, which is in the top 0.8% of all scored CVEs.
Exploitation in the next 30 days is more likely than not, according to EPSS.
What to do
- Update Samba to 4.16.11 or 4.17.10 or 4.18.5, whichever matches your release line, or a later version.
- Read the advisory on samba.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.2 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Virtualization 4 for Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Storage 3 | Not specified in the record | Not stated |
| Samba | Samba | before 4.16.11; 4.17.0 up to, but not including, 4.17.10; 4.18.0 up to, but not including, 4.18.5 | 4.16.11, 4.17.10, 4.18.5 |
| Fedora Project | Fedora | 37; 38 | Not stated |
| Red Hat | Enterprise Linux | 8.0; 9.0 | Not stated |
| Debian | Debian Linux | 11.0; 12.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official 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: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Loop with Unreachable Exit Condition
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
More Loop with Unreachable Exit Condition vulnerabilities (CWE-835)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- access.redhat.com/errata/RHSA-2023:6667Third Party Advisory
- access.redhat.com/errata/RHSA-2023:7139Third Party Advisory
- access.redhat.com/security/cve/CVE-2023-34966Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2222793Issue Tracking, Third Party Advisory
Other references
- access.redhat.com/errata/RHSA-2024:0423
- access.redhat.com/errata/RHSA-2024:0580
- access.redhat.com/errata/RHSA-2024:4101
- lists.fedoraproject.org/archives/list/[email protected]/message/BPCSGND7LO467AJGR5DYBG…
- lists.fedoraproject.org/archives/list/[email protected]/message/OT74M42E6C36W7PQVY3OS4…
- security.netapp.com/advisory/ntap-20230731-0010/
- debian.org/security/2023/dsa-5477
Other vulnerabilities in Red Hat Enterprise Linux 8
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
Recent Loop with Unreachable Exit Condition vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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