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CVE-2026-23533

Freerdp buffer overflow

9.8 CRITICALPublic exploitEPSS 0.52%
  1. Published19 Jan 2026

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Freerdp< 3.21.0

Remediation

Fixed in
Freerdp≥ 3.21.0

References

and 10 more references

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Frequently asked

Is CVE-2026-23533 being actively exploited?

CVE-2026-23533 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.52%.

How severe is CVE-2026-23533?

CVE-2026-23533 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.52% probability of exploitation.

Which products are affected by CVE-2026-23533?

Affected products include Freerdp.

How do I fix CVE-2026-23533?

Upgrade affected software to a fixed version, for example Freerdp 3.21.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-23533 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.