CVE-2026-33897

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{"affected": [{"affectedData": [{"product": "incus", "vendor": "lxc", "versions": [{"status": "affected", "version": "< 6.23.0"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:linuxcontainers:incus:*:*:*:*:*:*:*:*", "matchCriteriaId": "CBE3ABCB-1D47-4A45-A09A-C9F609C53131", "versionEndExcluding": "6.23.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Incus is a system container and virtual machine manager. Prior to version 6.23.0, instance template files can be used to cause arbitrary read or writes as root on the host server. Incus allows for pongo2 templates within instances which can be used at various times in the instance lifecycle to template files inside of the instance. This particular implementation of pongo2 within Incus allowed for file read/write but with the expectation that the pongo2 chroot feature would isolate all such access to the instance's filesystem. This was allowed such that a template could theoretically read a file and then generate a new version of said file. Unfortunately the chroot isolation mechanism is entirely skipped by pongo2 leading to easy access to the entire system's filesystem with root privileges. Version 6.23.0 patches the issue."}, {"lang": "es", "value": "Incus es un gestor de contenedores de sistema y m\u00e1quinas virtuales. Antes de la versi\u00f3n 6.23.0, los archivos de plantilla de instancia pueden usarse para causar lecturas o escrituras arbitrarias como root en el servidor anfitri\u00f3n. Incus permite plantillas pongo2 dentro de las instancias que pueden usarse en varios momentos del ciclo de vida de la instancia para crear plantillas de archivos dentro de la instancia. Esta implementaci\u00f3n particular de pongo2 dentro de Incus permit\u00eda la lectura/escritura de archivos, pero con la expectativa de que la caracter\u00edstica chroot de pongo2 aislar\u00eda todo ese acceso al sistema de archivos de la instancia. Esto se permit\u00eda de tal manera que una plantilla podr\u00eda te\u00f3ricamente leer un archivo y luego generar una nueva versi\u00f3n de dicho archivo. Desafortunadamente, el mecanismo de aislamiento chroot es completamente omitido por pongo2, lo que lleva a un f\u00e1cil acceso a todo el sistema de archivos del sistema con privilegios de root. La versi\u00f3n 6.23.0 parchea el problema."}], "id": "CVE-2026-33897", "lastModified": "2026-06-17T10:38:16.753", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.9, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.1, "impactScore": 6.0, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33897", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-03-27T20:02:45.794604Z", "version": "2.0.3"}}]}, "published": "2026-03-26T23:16:20.743", "references": [{"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/lxc/incus/security/advisories/GHSA-83xr-5xxr-mh92"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1336"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "incus: pongo2: Incus: Arbitrary file read/write as root via pongo2 template chroot bypass", "id": "2452020", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452020"}, "csaw": false, "cvss3": {"cvss3_base_score": "9.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L", "status": "draft"}, "cwe": "CWE-243", "details": ["A flaw was found in Incus, a system container and virtual machine manager. An attacker with control over instance template files can exploit a vulnerability in the pongo2 templating engine. This flaw allows for arbitrary read or write operations as the root user on the host server by bypassing the intended chroot isolation mechanism. This can lead to unauthorized access and modification of critical system files."], "name": "CVE-2026-33897", "public_date": "2026-03-26T22:43:31Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-33897\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-33897\nhttps://github.com/lxc/incus/security/advisories/GHSA-83xr-5xxr-mh92"], "statement": "This Important flaw in Incus, a system container and virtual machine manager, allows an attacker with control over instance template files to bypass chroot isolation. This enables arbitrary file read or write operations as the root user on the host server. This vulnerability affects Incus, which is available as a community project.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,6.23.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "incus", "source": "cna", "vendor": "lxc"}, "product": "incus", "vendor": "lxc"}], "analysis": {"en": {"generated_at": "2026-03-30T20:39:51.900826+00:00", "value": {"mitigation_remediation": ["Apply the vendor patch to upgrade Incus to version 6.23.0 or later", "Ensure that any remaining instances are rebuilt from clean templates to eliminate residual risks", "Reconfigure Incus to disable or tightly restrict arbitrary pongo2 template execution where possible", "Continuously monitor system logs for unexpected template activity or file manipulation"], "summary": {"action": "Immediate Patch", "impact": "Privilege Escalation \u2013 arbitrary root file read/write"}, "threat_synthesis": {"affected_systems": "All Incus installations running versions earlier than 6.23.0 are impacted. The vulnerability affects the core Incus product from Linux Containers, regardless of deployment mode. No additional vendor or product variations are reported.", "description_and_impact": "Incus, a system container and virtual machine manager, contains a flaw in its use of pongo2 templates that allows an attacker to read or modify any file on the host system with root privileges. The vulnerability arises because the chroot isolation intended to confine template execution is bypassed, enabling the template to access the entire host filesystem. This weakness corresponds to CWE\u20111336 (Improper Validation of Runtime Parameters) and CWE\u2011243 (Resource Disconnection Without Cleanup). The result is a serious threat to confidentiality, integrity, and availability, since an attacker could exfiltrate sensitive data, alter critical system files, or even deploy malicious code.", "risk_and_exploitability": "The CVSS score of 10 indicates maximal severity, and the EPSS score of below 1% suggests the likelihood of real\u2011world exploitation is low at present. However, because the attack requires only the ability to supply a pongo2 template to an instance, the potential attack vector is relatively simple once an instance is reachable. The vulnerability is not listed in the CISA KEV catalog, but its high impact warrants immediate attention. Once exploited, an attacker gains full read/write access to the host filesystem, effectively compromising the entire platform."}}}}, "created": "2026-03-27T08:31:28.481030+00:00", "updated": "2026-03-30T20:57:21.444869+00:00", "vendors": ["lxc", "lxc$PRODUCT$incus"]}