Is CVE-2026-33977 in the CISA KEV catalog?

No. CVE-2026-33977 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-33977?

CVE-2026-33977 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2026-33977?

CVE-2026-33977 has an EPSS score of 0.26% (17th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-33977?

Upgrade freerdp to 3.24.2 or later.

CVE & CISA-KEV Catalog

CVE-2026-33977

MEDIUM

6.5

CVSS v3

NVD

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, a malicious RDP server can crash the FreeRDP client by sending audio data in IMA ADPCM format with an invalid initial step index value (>= 89). The unvalidated step index is read directly from the network and used to index into a 89-entry lookup table, triggering a WINPR_ASSERT() failure and process abort via SIGABRT. This affects any FreeRDP client that has audio redirection (RDPSND) enabled, which is the default configuration. This issue has been patched in version 3.24.2.

CWE-617

How to fix

Remediation Available

freerdpNVD

Affected:< 3.24.2Fixed in:3.24.2CVE-2026-33977derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Exploit Intelligence

0.26%probability of exploitation in 30 days

17thpercentile

Low risk: more likely to be exploited than 17% of all known CVEs.

References

Patch2

Related Vulnerabilities

Other CWE-617 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-8617	High	7.5	93%	-	Fix
CVE-2020-36222	High	7.5	78%	-	Fix
CVE-2006-5779	High	7.5	75%	-	Fix
CVE-2021-27212	High	7.5	64%	-	Fix
CVE-2018-5740	High	7.5	59%	-	Fix
CVE-2023-28425	Medium	5.5	55%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-01.