Medium [CVE-2026-56117] Local heap use-after-free vulnerability leads to denial of service.
This medium-severity Red Hat Linux advisory covers CVE-2026-56117 affecting Red Hat Enterprise Linux 10, Red Hat package: dhcpcd.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
dhcpcd through 10.3.2, fixed in commit 78ea09e, contains a heap use-after-free vulnerability in the control socket handling within src/control.c that allows local unprivileged attackers to trigger memory corruption when privilege separation is disabled.
Attackers can connect to the control socket and send a privileged command such as -x, causing control_recvdata() to free the client object while the same READ+HANGUP event subsequently reaches control_hangup() with the stale pointer, resulting in a use-after-free condition exploitable in deployments using --disable-privsep or where privsep initialization has failed with the control socket operating in mode 0666.
A flaw was found in dhcpcd. This occurs when privilege separation is disabled, enabling the attacker to send a privileged command to the control socket.
Successful exploitation can lead to a denial of service. Red Hat severity: Moderate — CVSS 4.7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-825. Affected Red Hat products: Red Hat Enterprise Linux 10.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: dhcpcd.
Is CVE-2026-56117 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-56117 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-56117?
Upgrade to a fixed release named by Red Hat:
- 10.3.2
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Mitigation checklist
- Ensure that the `dhcpcd` service is configured to run with privilege separation enabled. If `dhcpcd` is running with privilege separation disabled (e.g., via `--disable-privsep`), re-enable it to prevent local unprivileged attackers from exploiting this vulnerability. If privilege separation cannot be enabled, restrict access to the system running `dhcpcd` or disable the `dhcpcd` service if it is not critical for network operations. If the `dhcpcd` service is reconfigured, a restart may be required for changes to take effect.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Get an email when Red Hat RHEL & SELinux publishes the next one.
See Red Hat RHEL & SELinux's last 90 days of advisories first. Then choose one product with live alerts free for life, or a free month of real-time alerts on everything with the severity, the fixed version and the vendor's link (card needed, then US$15/month; we email you before the first charge).
More Red Hat Linux advisories
- CVE-2026-111497Oct 22, 2026Out-of-Bounds Write in Google Brotli Decoder
- CVE-2026-109619Oct 21, 2026fatal error handling retains stale request state leading to use-after-free
- CVE-2026-109618Oct 21, 2026OOM bailout during request parsing leads to memory corruption and RCE
- CVE-2026-119977Oct 31, 2026Arbitrary code execution via predictable upgrade staging paths
- CVE-2026-97229Oct 13, 2026integer overflow issue in CI/CD regular expression compiler
- CVE-2026-64849Aug 17, 2026Unauthenticated full-read SSRF in webhook delivery: _validate_webhook_url bypassed
iPhone and Android apps · New on the App Store
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 34 official vendor sources and 160+ reviewed platform categories.
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.