Riskcovery

CVE-2026-22858

FreeRDP has a global-buffer-overflow in crypto_base64_decode

State
Published
Severity
5.6 Medium
Published
Jan 14, 2026
Updated
Aug 19, 2026
Reserved
Jan 12, 2026

Read the record on cve.org

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, global-buffer-overflow was observed in FreeRDP's Base64 decoding path. The root cause appears to be implementation-defined char signedness: on Arm/AArch64 builds, plain char is treated as unsigned, so the guard c <= 0 can be optimized into a simple c != 0 check. As a result, non-ASCII bytes (e.g., 0x80-0xFF) may bypass the intended range restriction and be used as an index into a global lookup table, causing out-of-bounds access. This vulnerability is fixed in 3.20.1.

Scores

CVSSScoreVectorSource
4.05.6 MediumCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:PGitHub_M
3.17.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:Hredhat-SADP

Weaknesses

  • CWE-125 Out-of-bounds Read
  • CWE-758 Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
  • CWE-787 Out-of-bounds Write

Affected Products

ProductVersions
FreeRDPFreeRDP
  • < 3.20.1Affected

References

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