Heap-based Buffer Overflow Affecting libwinpr package, versions <2:3.10.3-12.el10_2.8


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.91% (59th percentile)

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  • Snyk IDSNYK-ALMALINUX10-LIBWINPR-18818975
  • published15 Aug 2026
  • disclosed13 Aug 2026

Introduced: 13 Aug 2026

CVE-2026-64620  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:10 libwinpr to version 2:3.10.3-12.el10_2.8 or higher.
This issue was patched in ALSA-2026:54486.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libwinpr package and not the libwinpr package as distributed by AlmaLinux. See How to fix? for AlmaLinux:10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1