CVSS 4.0
5.6 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:PCVE-2026-22858
Medium (5.6) in freerdp freerdp. EPSS 0.7% chance of exploitation in the next 30 days.
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.
Severity
CVSS 3.1
9.1 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H- EPSS
- 0.7% chance of exploitation in the next 30 days; higher than 53% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-125, CWE-758, CWE-787
- Published
- Modified
- Record from
- the NVD, synced
Affected
- freerdp:freerdp