CVE-2026-33897 | Incus vulnerable to arbitrary file read and write through pongo templates

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.

Published: 2026-03-26 Last update: 2026-03-30 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-33897 is rated Moderate Risk (41.5/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.02%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33897

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-21 0.06% 0.02% -0.04%
2 2026-04-01 0.05% 0.06% +0.01%
3 2026-03-27 0.05%

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33897

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.9 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.1 6.0 [email protected]

Weakness enumeration for CVE-2026-33897

GitHub Security Advisory for CVE-2026-33897

GHSA-83xr-5xxr-mh92 · Severity: critical · Ecosystem: go — Incus vulnerable to arbitrary file read and write through pongo templates

OS Trackers for CVE-2026-33897

vendor priority summary link
alpine CVE-2026-33897: 1 source package rows (incus); 31 state rows across 2 repos (3.23-community, edge-community); fixed 0, open 31. https://security.alpinelinux.org/vuln/CVE-2026-33897
debian not yet assigned CVE-2026-33897 not yet assigned priority: Debian including 2 source packages (incus, lxd), 5 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-33897
redhat high https://access.redhat.com/security/cve/CVE-2026-33897
suse high CVE-2026-33897 severity important: SUSE including 5 source package names (incus-6.23-1.1, incus-bash-completion-6.23-1.1, incus-fish-completion-6.23-1.1, incus-tools-6.23-1.1, incus-zsh-completion-6.23-1.1), 5 product×package rows across 1 product lines (openSUSE Tumbleweed): Fixed 5. https://www.suse.com/security/cve/CVE-2026-33897/
ubuntu medium CVE-2026-33897 medium priority: Ubuntu including 2 source packages (incus, lxd), 11 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): needs-triage 5, DNE 4, not-affected 1, released 1. https://ubuntu.com/security/CVE-2026-33897

Affected software / configurations for CVE-2026-33897

Vendor Product Version Raw CPE
linuxcontainers incus < 6.23.0 cpe:2.3:a:linuxcontainers:incus:*:*:*:*:*:*:*:*

References for CVE-2026-33897

cvelogic Threat Intelligence