# CVE-2026-55659: Grist: XSS through unsafe value interpolation in server-rendered pages

> Attackers can inject scripts via document names or OAuth parameters to execute code in victims' sessions, potentially escalating privileges to owner level.

- **Severity:** High 7.7 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Jul 2026
- **Updated:** 13 Jul 2026
- **Also known as:** GHSA-6qrq-h2h6-cw54

## What is CVE-2026-55659?

CVE-2026-55659 is a high-severity cross-site scripting vulnerability in gristlabs grist-core, published on 10 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Grist is spreadsheet software using Python as its formula language. Prior to 1.7.15, several server-rendered Grist pages embedded user-controlled values into the page and into inline scripts without fully escaping them, allowing cross-site scripting. On the main application page, a document's name or description, set by a document editor, is rendered into the page that other users load when opening the document. On the OAuth2 end-of-flow page, the openerOrigin request parameter was reflected back into the served page. Injected script runs in the victim's Grist origin and can act through the authenticated session, reading or modifying data and changing sharing settings and access rules. A document editor could therefore escalate to owner-level access. This issue is fixed in version 1.7.15.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-55659?


## How do I fix CVE-2026-55659?

No fix has been published for CVE-2026-55659 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55659 being exploited?

There is no known exploitation of CVE-2026-55659 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55659 and fix it if it is affected.

What it is: CVE-2026-55659 is a high-severity cross-site scripting vulnerability in gristlabs grist-core, published on 10 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-55659 in the wild and no public exploit code.

Affected product: gristlabs grist-core. 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-2026-55659/ (Markdown: https://insights.sbomify.com/CVE-2026-55659/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55659
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55659
- OSV: https://osv.dev/vulnerability/CVE-2026-55659

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55659/
Summaries are generated and may contain mistakes; the official description above is the record.