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Vulnerabilities

Security research · CVE-2026-22858

FreeRDP is a free implementation of the Remote Desktop Protocol.

Published Jan 14, 2026 · catalog updated Aug 19, 2026 · FreeRDP FreeRDP

Last checked Oct 29, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-22858. EPSS is 0.70%. Act only if a listed version of FreeRDP FreeRDP is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.70%
Remediation
Version ranges on file
Affected products
vendor FreeRDP FreeRDP < 3.20.1

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor FreeRDP FreeRDP < 3.20.1< 3.20.1

How to fix CVE-2026-22858

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-22858. EPSS is 0.70%. Act only if a listed version of FreeRDP FreeRDP is installed.

Which versions are affected?

Compare what you have installed with FreeRDP FreeRDP < 3.20.1 < 3.20.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.70%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 14, 2026 · EUVD

    Detected

    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 bypa

  2. Aug 19, 2026 · EUVD

    Updated

    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 bypa

Sources

  • CVE.orgVulnerability recordCVE-2026-22858

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-22858

    30-day exploitation probability 0.70%

    first.org
  • EUVDVulnerability recordEUVD-2026-2669

    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,

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 29, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 29, 2026
  • FIRST EPSSOct 29, 2026
  • EUVDOct 29, 2026