Skip to main content
CRITICAL

CVE-2026-22858

CVSS v3

9.1

CRITICAL

EPSS Score

0.7 %

exploit probability, as of 2026-10-18

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Get an alert for each new CVE published for freerdp.

Set up CVE WatchFree account · no credit card

Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • freerdpAlmaLinux:10all versions · fixed in 2:3.10.3-5.el10_1.2and 5 other packages
  • freerdpAlmaLinux:9all versions · fixed in 2:2.11.7-1.el9_7.2and 4 other packages
  • freerdpAlmaLinux:8all versions · fixed in 2:2.11.7-3.el8_10and 4 other packages

Vendor advisories

  • CVE-2026-22858 Red Hat Product Security732 products fixed · 5 known affected

    freerdp: FreeRDP global-buffer-overflow

    freerdp as a component of Red Hat Enterprise Linux 6 · freerdp-devel as a component of Red Hat Enterprise Linux 6 · freerdp-libs as a component of Red Hat Enterprise Linux 6

  • RHSA-2026:19033 Red Hat Product Security65 products fixed

    Red Hat Security Advisory: freerdp security update

  • RHSA-2026:4489 Red Hat Product Security35 products fixed

    Red Hat Security Advisory: freerdp security update

  • RHSA-2026:4471 Red Hat Product Security47 products fixed

    Red Hat Security Advisory: freerdp security update

  • RHSA-2026:4446 Red Hat Product Security72 products fixed

    Red Hat Security Advisory: freerdp security update

  • RHSA-2026:4440 Red Hat Product Security40 products fixed

    Red Hat Security Advisory: freerdp security update

9 more advisories

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Published
2026-01-14
Last Modified
2026-01-20

Frequently asked questions

What is CVE-2026-22858?

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.

Is CVE-2026-22858 actively exploited?

Active exploitation of CVE-2026-22858 has not been confirmed. Its EPSS score was 0.7% on 2026-10-18, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-22858?

CVE-2026-22858 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

Running freerdp? Hear about its next vulnerability

CVE Watch matches each new CVE to the vendors and products you list (vendor and product, not the version) and puts it in your alerts with its KEV and EPSS status.

Get alerts for this productCISA KEV additions, October 2026Search CVEs

Already have an account? Open CVE WatchNo credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database