# CVE-2026-73155: cti-transmute Missing Authorization Allows Reactions to Private Comments

> Authenticated users can modify reactions on private comments they cannot view, allowing unauthorized data modification in MISP cti-transmute.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/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:** 11 Aug 2026
- **Updated:** 11 Aug 2026
- **Also known as:** GHSA-rv36-q8cj-wgr9

## What is CVE-2026-73155?

CVE-2026-73155 is a medium-severity missing authorization vulnerability in MISP cti-transmute, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Affected versions of cti-transmute allow authenticated users to add or remove emoji reactions on comments without first checking whether those users are authorized to view the target comment.

The vulnerable react() handler passed an attacker-controlled comment_id directly to comments_repo.toggle_reaction() after only validating that the ID existed syntactically and that the requested emoji was permitted. Because comment-level visibility was not enforced, a user who could identify the ID of a private or otherwise inaccessible comment could modify reaction state on that comment despite lacking permission to access it.

The fix retrieves the target comment, rejects missing or deleted comments, retrieves its associated conversion, and enforces access.can_see_comment(current_user, comment, conversion). Unauthorized requests now receive HTTP 403.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-73155?


## How do I fix CVE-2026-73155?

No fix has been published for CVE-2026-73155 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73155 being exploited?

There is no known exploitation of CVE-2026-73155 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73155 and fix it if it is affected.

What it is: CVE-2026-73155 is a medium-severity missing authorization vulnerability in MISP cti-transmute, published on 11 Aug 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-2026-73155 in the wild and no public exploit code.

Affected product: MISP cti-transmute. 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-2026-73155/ (Markdown: https://insights.sbomify.com/CVE-2026-73155/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73155
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73155
- OSV: https://osv.dev/vulnerability/CVE-2026-73155

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73155/
Summaries are generated and may contain mistakes; the official description above is the record.