CVE-2026-128886
Dbus: server accept watch can be stalled by blocking nonce-tcp accept_with_noncefile path
A flaw was found in dbus when configured with the nonce-tcp transport. An unauthenticated attacker able to connect to an exposed listener can cause a Denial of Service (DoS) by opening a connection and withholding the expected authentication token. Because the server processes this verification without enforcing a timeout, the stalled connection blocks the accept process and prevents legitimate clients from establishing new connections.
Fixes and workarounds
Workaround
Disable non-standard `nonce-tcp` listeners in the D-Bus configuration in favor of standard UNIX domain sockets. If network reachability is required, restrict access to trusted hosts using `firewalld`. To remove an exposed port from an untrusted firewall zone: ``` firewall-cmd --permanent --zone=public --remove-port=<PORT>/tcp firewall-cmd --permanent --zone=trusted --add-source=<TRUSTED_IP_OR_SUBNET> firewall-cmd --reload ``` Caveats: Restricting or disabling network listeners prevents remote clients outside the trusted subnet from connecting to the affected bus. Warning: Reloading the firewall rules or altering the D-Bus server configuration requires restarting the affected D-Bus service, which will drop existing connections and temporarily disrupt communications.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 10 Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 6.2 medium |
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/security/cve/CVE-2026-128886CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2472930CNA: redhat · issue-tracking, x_refsource_REDHAT
For agents and automation
Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.
Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.
Endpoints and access details
https://api.y2.dev/api/v2/cyber/cveshttps://api.y2.dev/api/v2/cyber/cves/{cveId}
A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.
For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.