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NVD / CVE Program· CNA GitHub_M

CVE-2026-33977: FreeRDP: DoS via WINPR_ASSERT in IMA ADPCM audio decoder (dsp.c:331)

MediumCVSS 6.9 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 27/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.26% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: FreeRDP FreeRDP 3.24.2.

Low priority for now. Upgrade to FreeRDP FreeRDP 3.24.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Mar 30, 2026
Updated
Jun 17, 2026
EPSS
0.2% · 18th percentile

Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
27 / 40 · 6.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.9
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-33977

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
freerdpfreerdp

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • FreeRDP FreeRDP

    • < 3.24.2affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • freerdp freerdpbefore 3.24.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.23freerdpbefore 3.24.2-r03.24.2-r0
Debian:12freerdp2from 0—
Debian:13freerdp3before 3.15.0+dfsg-2.1+deb13u23.15.0+dfsg-2.1+deb13u2
Debian:14freerdp3before 3.24.2+dfsg-13.24.2+dfsg-1
openSUSE:Tumbleweedfreerdpbefore 3.24.2-1.13.24.2-1.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7freerdpbefore 3.10.3-150700.3.17.13.10.3-150700.3.17.1

Same product

freerdp: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-8787FreeRDP prior to version 2.0.0-rc4 contains an Integer Overflow that leads to a Heap-Based Buffer Overflow in function…
    42Plan
  • CVE-2018-8788FreeRDP prior to version 2.0.0-rc4 contains an Out-Of-Bounds Write of up to 4 bytes in function nsc_rle_decode() that results in a memory…
    41Plan
  • CVE-2018-8786FreeRDP prior to version 2.0.0-rc4 contains an Integer Truncation that leads to a Heap-Based Buffer Overflow in function…
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-31897Mar 13, 2026 · FreeRDP has an out-of-bounds read in `freerdp_bitmap_decompress_planar`
    36Monitor
  • ← EarlierCVE-2026-33952Mar 30, 2026 · FreeRDP: DoS via WINPR_ASSERT in rts_read_auth_verifier_no_checks
    24Monitor
  • Later →CVE-2026-33982Mar 30, 2026 · FreeRDP: Persistent Cache Allocator Mismatch - Heap OOB Read
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
FreeRDP FreeRDP3.24.2 · descriptionVendor (CNA)
alpine:freerdp3.24.2-r0 · Alpine:v3.23Package registry (OSV)
debian:freerdp33.15.0+dfsg-2.1+deb13u2 · Debian:13Package registry (OSV)
opensuse:freerdp3.24.2-1.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:freerdp3.10.3-150700.3.17.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-121951219 days apartFreeRDP 3.0.0 before 3.32.2 Denial of Service via Slow-Path Input Event
    34Monitor
  • CVE-2026-121960219 days apartFreeRDP before 3.32.2 Unauthenticated Denial of Service via CredSSP TSRequest
    34Monitor
  • CVE-2026-121409218 days apartFreeRDP before 3.32.2 Denial of Service via Oversized X.224 Routing Token
    32Monitor
  • CVE-2026-91951169 days apartFreeRDP 3.14.0 through 3.30.0 Out-of-bounds Write via urbdrc
    28Monitor
  • CVE-2026-91961169 days apartFreeRDP before 3.31.0 Denial of Service via URBDRC
    28Monitor
  • CVE-2026-109678197 days apartFreeRDP 3.0.0-beta1 before 3.32.0 Reachable Assertion via Emulated SCardStatusA
    28Monitor

Not on record for this CVE: EPSS history · researcher credit · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-617 · Reachable Assertion

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records