CVE-2026-22858
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, service disruption.
- Exploit odds
- 0.7% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.7% in the next 30 days (EPSS).
- Severity: 5.6 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.7% · EPSS, next 30 days
- Weakness
- CWE-125 · Out-of-bounds read
- Record status
- Modified
Affected
- Freerdp < 3.20.1
Attack profile CVSS 4.0 · 5.6
- Attack vector
- Network
- Complexity
- High
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- Passive
- Confidentiality
- High
- Integrity
- None
- Availability
- High
Raw vector
CVSS: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:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-22858.md and follow it. Check whether this project is affected by CVE-2026-22858. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896
References
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896
- https://access.redhat.com/errata/RHSA-2026:19033
- https://access.redhat.com/errata/RHSA-2026:3067
- https://access.redhat.com/errata/RHSA-2026:3068
- https://access.redhat.com/errata/RHSA-2026:3334
- https://access.redhat.com/errata/RHSA-2026:3975
- https://access.redhat.com/errata/RHSA-2026:4121
- https://access.redhat.com/errata/RHSA-2026:4433
- https://access.redhat.com/errata/RHSA-2026:4437
- https://access.redhat.com/errata/RHSA-2026:4438
- https://access.redhat.com/errata/RHSA-2026:4439
- https://access.redhat.com/errata/RHSA-2026:4440
- https://access.redhat.com/errata/RHSA-2026:4446
- https://access.redhat.com/errata/RHSA-2026:4471
- https://access.redhat.com/errata/RHSA-2026:4489
- https://access.redhat.com/security/cve/CVE-2026-22858
- https://bugzilla.redhat.com/show_bug.cgi?id=2429649
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-22858.json