How severe is CVE-2026-55194?

CVE-2026-55194 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-55194 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-55194?

CVE-2026-55194 affects Freerdp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-55194?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-55194 published?

CVE-2026-55194 was published on 2026-08-19 and last updated on 2026-09-24.

CVE-2026-55194

CVE-2026-55194 is a critical-severity vulnerability in Freerdp with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 8.7
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-122
Affected product: Freerdp
Published: 2026-08-19
Last modified: 2026-09-24

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu->s buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0.

Frequently asked questions

What is CVE-2026-55194?: FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu->s buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0.
How severe is CVE-2026-55194?: CVE-2026-55194 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-55194 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-55194?: CVE-2026-55194 affects Freerdp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-55194?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-55194 published?: CVE-2026-55194 was published on 2026-08-19 and last updated on 2026-09-24.

References

Affected products (1)

cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*

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