runc CVE-2026-41579

Exploitation requires that a victim operator or automated system pulls and executes a container image that the attacker controls or has tampered with, specifically one where /dev is a symbolic link rather than a real directory within the image's root filesystem bundle. runc must process this image during container initialization - the symlink is only followed during the device-node or bind-mount setup phase, not arbitrarily at runtime. The attack is limited to environments where the attacker can influence which container images are executed: public CI pipelines without image signing, shared registries with write access, or supply-chain-compromised base images. Fully automated pull-and-run pipelines (e.g., Kubernetes admission without image verification) reduce the user-interaction barrier significantly. The explicitly 'limited' impact qualifier indicates that not all host paths are reachable and a full interactive shell or container escape is not achievable through this vector alone. Authentication requirements are not confirmed from available data, as no CVSS vector has been assigned.

No CVSS score or vector has been assigned; this is a pre-NVD disclosure with a single oss-security source. EPSS data is unavailable. Exploitation is not confirmed by CISA KEV and no public exploit code exists at time of analysis. The disclosure explicitly bounds the impact as 'limited' integrity violations, distinguishing this from a full container breakout, which lowers severity compared to prior runc escape CVEs. However, runc's pervasiveness across containerized infrastructure - CI/CD pipelines, Kubernetes nodes, shared build environments - means even a bounded host-write primitive carries meaningful real-world risk in multi-tenant contexts where an attacker can influence the images being executed. Attack complexity is low if image supply chain controls are absent. The 'limited' characterization is inferred solely from the oss-security summary title and has not been independently quantified; defenders should treat the actual scope as unconfirmed until a vendor advisory or NVD entry provides specifics.

An attacker publishes a malicious container image to a public or private registry accessible to a target CI/CD pipeline, with the image's root filesystem containing /dev as a symbolic link pointing to a sensitive host directory such as /etc. When an automated build system or operator pulls and runs the image via runc, the runtime follows the symlink during /dev population, inadvertently creating or overwriting files on the host outside the container boundary. No public exploit code has been identified at time of analysis, but the attack primitive is straightforward for anyone familiar with runc's container setup internals.