# CVE-2026-22853: FreeRDP heap buffer overflow in RDPEAR NDR array reader

Source: https://junglewise.ai/threats/cve-2026-22853-freerdp-heap-buffer-overflow-in-rdpear-ndr-array-reader  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-01-14. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

CVE-2026-22853 · Severity: critical · CVSS 9.8 · Published 2026-01-14

FreeRDP is an open-source tool used to connect to remote computers via the Remote Desktop Protocol (RDP). A security flaw in how the software handles certain data packets could allow a malicious server to crash the client application or potentially execute unauthorized code on the user's machine. This could lead to a full system compromise or the theft of sensitive data from the user's session.

Technologies: [FreeRDP](https://junglewise.ai/threats/technologies/freerdp), [Red Hat Enterprise Linux 6](https://junglewise.ai/threats/technologies/enterprise-linux-6), [Red Hat Enterprise Linux AppStream](https://junglewise.ai/threats/technologies/enterprise-linux-appstream). Vendors: [FreeRDP](https://junglewise.ai/threats/vendors/freerdp), [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2026-22853 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-22853 being exploited in the wild.

**How severe is CVE-2026-22853?** Critical severity, with a CVSS score of 9.8, published 14 January 2026.

**Which products and versions are affected?** FreeRDP < 3.20.1; Red Hat Enterprise Linux 6 6; Red Hat Enterprise Linux AppStream 10.0, 10.1, 10.2.

**Is there a fix for CVE-2026-22853?** A patch was published on 2026-01-14: FreeRDP version 3.20.1 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-22853 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-22853?** Check whether you run FreeRDP, Red Hat Enterprise Linux 6 or Red Hat Enterprise Linux AppStream at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap-based buffer overflow exists in FreeRDP's RDPEAR (Remote Desktop Protocol Enhanced Authentication and RestrictedAdmin) component within the NDR (Network Data Representation) array reader. The function 'ndr_read_pointedMessageEx' allocates a buffer based on 'hints->count', but the subsequent call to 'ndr_read_uconformant_array' reads an element count directly from the network stream without verifying it against the allocated size. An attacker-controlled 'count' larger than the 'hints' value results in an out-of-bounds write during the uint8 array reading loop. This vulnerability can be triggered by a malicious RDP server or a man-in-the-middle attacker to achieve remote code execution or a denial-of-service on the client. The issue is resolved in version 3.20.1.

## Affected products

- FreeRDP FreeRDP < 3.20.1
- Red Hat Red Hat Enterprise Linux AppStream 10.0, 10.1, 10.2
- Red Hat Red Hat Enterprise Linux 6 6

## Timeline

- 2026-01-14: advisory: GitHub Security Advisory GHSA-47v9-p4gp-w5ch published
- 2026-01-14: patched: FreeRDP version 3.20.1 released
- 2026-01-14: disclosed: CVE-2026-22853 published
- 2026-05-19: patched: Red Hat released security updates for RHEL 10

## References

- [https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1](https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1)
- [https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-47v9-p4gp-w5ch](https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-47v9-p4gp-w5ch)
- [https://access.redhat.com/errata/RHSA-2026:19033](https://access.redhat.com/errata/RHSA-2026:19033)
- [https://access.redhat.com/errata/RHSA-2026:3068](https://access.redhat.com/errata/RHSA-2026:3068)
- [https://access.redhat.com/errata/RHSA-2026:4121](https://access.redhat.com/errata/RHSA-2026:4121)
- [https://access.redhat.com/security/cve/CVE-2026-22853](https://access.redhat.com/security/cve/CVE-2026-22853)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2429647](https://bugzilla.redhat.com/show_bug.cgi?id=2429647)

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- [FreeRDP heap out-of-bounds write in RDPGFX HashTable_GetKeys](https://junglewise.ai/threats/cve-2026-121958-freerdp-through-3-32-1-has-a-heap-out-of-bounds-write-in-the)