NVD / CVE Program· CNA GitHub_M

CVE-2026-33898: Local Incus UI web server vulnerable to nuthentication bypass

Noroxi assessment

Priority: Monitor (action score 35/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.35% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
Fixed version: incus (Debian:14) 7.0.0-1; github.com/lxc/incus/v6 (Go) 6.23.0; github.com/lxc/incus/v6/cmd/incus (Go) 6.23.0.

Low priority for now. Upgrade to incus (Debian:14) 7.0.0-1; github.com/lxc/incus/v6 (Go) 6.23.0; github.com/lxc/incus/v6/cmd/incus (Go) 6.23.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Incus is a system container and virtual machine manager. Prior to version 6.23.0, the web server spawned by `incus webui` incorrectly validates the authentication token such that an invalid value will be accepted. `incus webui` runs a local web server on a random localhost port. For authentication, it provides the user with a URL containing an authentication token. When accessed with that token, Incus creates a cookie persisting that token without needing to include it in subsequent HTTP requests. While the Incus client correctly validates the value of the cookie, it does not correctly validate the token when passed int the URL. This allows for an attacker able to locate and talk to the temporary web server on localhost to have as much access to Incus as the user who ran `incus webui`. This can lead to privilege escalation by another local user or an access to the user's Incus instances and possibly system resources by a remote attack able to trick the local user into interacting with the Incus UI web server. Version 6.23.0 patches the issue.

HighCVSS 8.8 · v3.1—No exploit Fix available

Published: Mar 26, 2026
Updated: Jun 17, 2026
EPSS: 0.3% · 28th percentile
CWE: CWE-287

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 8.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linuxcontainers	incus	cpe:2.3:a:linuxcontainers:incus

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linuxcontainers incusbefore 6.23.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

lxc incus
- < 6.23.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:13	incus	from 0	—
Debian:14	incus	before 7.0.0-1	7.0.0-1
Go	github.com/lxc/incus	from 0	—
Go	github.com/lxc/incus/v6	before 6.23.0	6.23.0
Go	github.com/lxc/incus/v6/cmd/incus	before 6.23.0	6.23.0
openSUSE:Tumbleweed	incus	before 6.23-1.1	6.23-1.1

Same product

linuxcontainers: all records

Other highest-scoring records for the same primary product.

CVE-2026-33897Incus vulnerable to arbitrary file read and write through pongo templates
39Monitor
CVE-2026-33945Abitrary file write through systemd-creds option
38Monitor
CVE-2026-23954Incus container image templating arbitrary host file read and write
34Monitor

Published before and after this one in the same product

← EarlierCVE-2026-33711Mar 26, 2026 · Incus vulnerable to local privilege escalation through VM screenshot path
18Monitor
← EarlierCVE-2026-33743Mar 26, 2026 · Incus vulnerable to denial of source through crafted bucket backup file
26Monitor
Later →CVE-2026-35527May 5, 2026 · Incus blind SSRF via image import preflight HEAD request
21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
debian:incus	7.0.0-1 · Debian:14	Package registry (OSV)
Go:github.com/lxc/incus/v6	6.23.0	Package registry (OSV)
Go:github.com/lxc/incus/v6/cmd/incus	6.23.0	Package registry (OSV)
opensuse:incus	6.23-1.1 · openSUSE:Tumbleweed	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

—

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

CVE-2026-338970 days apartIncus vulnerable to arbitrary file read and write through pongo templates
39Monitor
CVE-2026-339450 days apartAbitrary file write through systemd-creds option
38Monitor
CVE-2026-2395463 days apartIncus container image templating arbitrary host file read and write
34Monitor
CVE-2026-3552740 days apartIncus blind SSRF via image import preflight HEAD request
21Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
A user must open a link or visit a page.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1app.use("/admin", requireSession, adminRouter);
2

3// Route added later skips the middleware
4app.post("/admin-api/config", updateConfig);

Fixed

1const admin = express.Router();
2admin.use(requireSession, requireRole("admin"));
3

4admin.post("/config", updateConfig);
5app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/lxc/incus/security/advisories/GHSA-453r-g2pg-cxxq

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records