# CVE-2026-100833: Contrast before 1.23.1 Image Substitution via Policy Generation

> Attackers with Kata agent access can bypass image integrity checks to substitute malicious container images, compromising confidential computing guarantees.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Sep 2026
- **Updated:** 9 Oct 2026
- **Also known as:** GHSA-m2qg-wrxv-h898, GHSA-mjj6-px65-jq92

## What is CVE-2026-100833?

CVE-2026-100833 is a high-severity vulnerability in edgelesssys contrast, published on 27 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Contrast (edgelesssys/contrast) versions 1.14.0 before 1.23.1 generate runtime policies that fail to detect all container image substitutions. A bad rebase during a Kata Containers update accidentally introduced an `allow_storage` rule that accepts storage entries using the `image_guest_pull` driver without verifying the image digest. An attacker with access to the Kata agent API — for example, a Kubernetes cluster administrator in Contrast's threat model — can therefore substitute a container image with an exploit payload, provided the substituted image satisfies the remaining policy rules, undermining the confidential container's integrity guarantees.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-100833?


## How do I fix CVE-2026-100833?

No fix has been published for CVE-2026-100833 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-100833 being exploited?

There is no known exploitation of CVE-2026-100833 in the wild and no public exploit code.

Public exploit code:

- Early Attestation Considered Very Harmful (CVE-2026-100833 of CVSS 9.6, CVE-2026-108265 of CVSS 9.1, CVE-2026-108266 of CVSS 9.1, CVE-2026-108267 of CVSS 9.1, CVE-2026-108268 of CVSS 9.1, CVE-2026-108269 of CVSS 9.1, CVE-2026-100835 of CVSS 9.1, CVE-2026-92701 of CVSS 9.1, CVE-2026-92702 of CVSS 9.1, CVE-2026-33697 of CVSS 7.5, and more to come) (github_poc): https://github.com/muhammad-usama-sardar/intra-handshake-fail

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100833 and fix it if it is affected.

What it is: CVE-2026-100833 is a high-severity vulnerability in edgelesssys contrast, published on 27 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-100833 in the wild and no public exploit code.

Affected product: edgelesssys contrast. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-100833/ (Markdown: https://insights.sbomify.com/CVE-2026-100833/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100833
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100833
- OSV: https://osv.dev/vulnerability/CVE-2026-100833

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100833/
Summaries are generated and may contain mistakes; the official description above is the record.