# CVE-2026-84962: Authenticated KMS request forgery via CRLF injection in GCP key identifier strings

> An attacker with write access can inject CRLF into key identifiers to force authenticated KMS API calls, escalating privileges and bypassing client-side encryption.

- **Severity:** Medium 5.7 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 3 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-84962, UBUNTU-CVE-2026-84962

## What is CVE-2026-84962?

CVE-2026-84962 is a medium-severity vulnerability in MongoDB libmongocrypt, published on 3 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

An unauthorized user with key vault write access may cause an authorized client to issue arbitrary authenticated Google Cloud KMS API calls under the authorized user's identity, escalating database-level access into cloud key control and defeating client-side encryption.

Weakness: CWE-93 (Improper Neutralization of CRLF Sequences)

## Which versions are affected by CVE-2026-84962?

It affects 1 product.


Products: Mongodb Libmongocrypt.

## How do I fix CVE-2026-84962?

Apply the vendor's patch.

## Is CVE-2026-84962 being exploited?

There is no known exploitation of CVE-2026-84962 in the wild and no public exploit code.

## Other vulnerabilities in MongoDB libmongocrypt

- [CVE-2026-106433](https://insights.sbomify.com/CVE-2026-106433/): Heap corruption via duplicate masterKey fields in MongoDB libmongocrypt (high 8.7)
- [CVE-2026-84971](https://insights.sbomify.com/CVE-2026-84971/): Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path (high 7.1)
- [CVE-2026-81523](https://insights.sbomify.com/CVE-2026-81523/): Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt (low 2.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-84962 and fix it if it is affected.

What it is: CVE-2026-84962 is a medium-severity vulnerability in MongoDB libmongocrypt, published on 3 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-84962 in the wild and no public exploit code.

Affected product: MongoDB libmongocrypt. 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-2026-84962/ (Markdown: https://insights.sbomify.com/CVE-2026-84962/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-84962
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84962
- OSV: https://osv.dev/vulnerability/CVE-2026-84962

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-84962/
Summaries are generated and may contain mistakes; the official description above is the record.