# CVE-2026-91945: FreeRDP before 3.31.0 Out-of-bounds Read via Smartcard ATR

> Authenticated RDP clients can trigger an out-of-bounds read in FreeRDP smartcard decoders, causing process termination and denial of service.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/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:** Yes
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-91945, GHSA-q65v-4w7q-hx3r, GHSA-w579-5rqc-5mqh, UBUNTU-CVE-2026-91945

## What is CVE-2026-91945?

CVE-2026-91945 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FreeRDP versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that fail to validate ATR length fields against fixed inline arrays. Authenticated RDP clients can send oversized ATR lengths in PAKID_CORE_DEVICE_IOCOMPLETION responses to trigger reads past stack or heap objects, causing process termination.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-91945?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-91945?

Upgrade to a fixed version.

## Is CVE-2026-91945 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91945 exists.

## Other vulnerabilities in Freerdp Freerdp

- [CVE-2021-37594](https://insights.sbomify.com/CVE-2021-37594/): Other in n/a (critical 9.8)
- [CVE-2021-37595](https://insights.sbomify.com/CVE-2021-37595/): Other in n/a (critical 9.8)
- [CVE-2026-67305](https://insights.sbomify.com/CVE-2026-67305/): FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr (critical 9.4)
- [CVE-2026-66402](https://insights.sbomify.com/CVE-2026-66402/): FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass (critical 9.3)
- [CVE-2026-67289](https://insights.sbomify.com/CVE-2026-67289/): FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91945 and fix it if it is affected.

What it is: CVE-2026-91945 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91945 exists.

Affected product: Freerdp Freerdp. 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-2026-91945/ (Markdown: https://insights.sbomify.com/CVE-2026-91945/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91945
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91945
- OSV: https://osv.dev/vulnerability/CVE-2026-91945

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91945/
Summaries are generated and may contain mistakes; the official description above is the record.