Vulnerability in freerdp (UBUNTU-CVE-2026-64620)

Summary

Vulnerability in freerdp (UBUNTU-CVE-2026-64620). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 3.30.0+dfsg-0ubuntu0.24.04.1 or later.

Original description

The description as published by the source.

FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length > out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decrypted into a fixed 32-byte buffer. Because the server publishes its RSA public key, an unauthenticated attacker can forge a ciphertext whose decrypted value is up to the full modulus length (e.g. 256 bytes for RSA-2048), overflowing the 32-byte heap buffer by up to ~224 attacker-controlled bytes pre-authentication, resulting in denial of service.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as UBUNTU-CVE-2026-64620 has been found in freerdp.
Successful exploitation can lead to full system takeover.
What to do: upgrade freerdp to 3.30.0+dfsg-0ubuntu0.24.04.1 or later.
If unsure, ask your IT team or search "freerdp UBUNTU-CVE-2026-64620" on the vendor's site.

UBUNTU-CVE-2026-64620 (freerdp)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 3.30.0+dfsg-0ubuntu0.24.04.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in freerdp.

📍 Affected scope

Check the vendor advisory for the affected versions of freerdp.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 3.30.0+dfsg-0ubuntu0.24.04.1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'freerdp' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'freerdp' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で freerdp を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade freerdp to 3.30.0+dfsg-0ubuntu0.24.04.1
```
ステージング環境で 3.30.0+dfsg-0ubuntu0.24.04.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。