Security readout for executives and security teams
Plain-English summary
A computer that is not intended to route traffic has IP forwarding turned on, meaning it can pass network packets between networks like a router would. On an ordinary server or workstation this is a misconfiguration that can let attackers use the machine as a stepping stone to reach networks that should have been isolated.
Executive priority
Low priority housekeeping item. Treat as part of standard system hardening rather than an incident. Ensure the configuration baseline enforces it and the compliance scanner reports on it, but no emergency action is warranted based on the cited public sources.
Technical view
CVE-1999-0511 is a configuration finding: IP forwarding is enabled on a host that is not designated as a router or firewall. Such a host may forward packets between attached network segments, potentially bypassing intended network segmentation and enabling traffic to reach hosts that should be unreachable. No specific product, version, or CVSS score is recorded for this entry.
Likely exposure
Exposure applies to endpoints, servers, or appliances that have IP forwarding enabled without a routing role, especially multi-homed hosts, VPN endpoints, virtualization hosts, or lab systems bridging segmented networks. Impact scales with how sensitive the reachable segments are.
Exploitation context
Not listed in CISA KEV and no public exploitation campaign is cited in the source bundle. This is a legacy configuration hygiene entry from 1999 rather than a discrete vulnerability, so exploitation depends on the attacker already having some access to the misconfigured host or its network.
Researcher notes
Entry is a legacy CVE with no vendor, product, CVSS, or CWE assigned, and only the CVE Program record is cited. Treat it as a configuration hygiene indicator rather than a software flaw. Any risk assessment must consider the specific host role, adjacent networks, and whether forwarding is intentional.
Mitigation direction
- Disable IP forwarding on hosts that are not designated routers or firewalls.
- Enforce a hardening baseline that sets IP forwarding off by default for servers and endpoints.
- Segment multi-homed hosts so a misconfigured forward cannot bridge trust zones.
- Review vendor and OS guidance for the correct forwarding setting per role.
- Monitor for unexpected changes to forwarding configuration via configuration management.
Validation and detection
- Inventory hosts and identify which are intended routers or firewalls.
- On non-routing hosts, check the OS setting that controls IPv4 and IPv6 forwarding and confirm it is disabled.
- Verify persistence of the setting across reboot using system configuration files.
- Cross-check firewall and network diagrams to confirm no host is silently bridging segments.
- Include the check in recurring configuration compliance scans.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-1999-0511 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cve.org/CVERecord?id=CVE-1999-0511CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.