CVE-2026-124740
Busybox: use-after-free of requested_ipv6 in udhcpc6
A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.
Fixes and workarounds
Workaround
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 6 Red Hat busybox
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat Hardened Images Red Hat busybox
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
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 / 4.3 medium |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | CNA: redhat |
| 3.1 / 4.3 medium |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/security/cve/CVE-2026-124740CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2571616CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-124740[email protected]
- https://bugzilla.redhat.com/show_bug.cgi?id=2571616[email protected]
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.