CVE-2026-22858

Summary

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.

Affected Software

VendorProductVersion RangeStatus
FreeRDPFreeRDP< 3.20.1affected

Weaknesses

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

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

freerdp: FreeRDP global-buffer-overflow

Additional References

References