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TI-2021-17998 Aliases CVE-2021-41159

Improper client input validation for FreeRDP gateway connections allows to overwrite memory

Priority MEDIUM 41CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.

Summary

FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. All FreeRDP clients prior to version 2.4.1 using gateway connections (`/gt:rpc`) fail to validate input data. A malicious gateway might allow client memory to be written out of bounds. This issue has been resolved in version 2.4.1. If you are unable to update then use `/gt:http` rather than /gt:rdp connections if possible or use a direct connection without a gateway.

Why it matters now

EPSS 0.01492 74th percentileScored 2026-11-07
Fix Fixed FreeRDP (FreeRDP): 2.4.1Red Hat: 5 advisories

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
FreeRDPFreeRDPbefore 2.4.12.4.1Patch availableCNA
  • FreeRDP VendorFreeRDP Affected before 2.4.1 Fixed in 2.4.1 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*before 2.4.1VulnerableFreeRDP
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
  • cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* Versions before 2.4.1 Vulnerable ·FreeRDP
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject

Remediation

  • Fix · CNA FreeRDP (FreeRDP) Fixed in 2.4.1

Red Hat 5 advisories

  • RHSA-2021:4619 Released 2021-11-11 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux Client (v. 7) freerdp-2.1.1-5.el7_9, freerdp-libs-2.1.1-5.el7_9, libwinpr-2.1.1-5.el7_9
    • Red Hat Enterprise Linux Client Optional (v. 7) freerdp-devel-2.1.1-5.el7_9, libwinpr-devel-2.1.1-5.el7_9
    • Red Hat Enterprise Linux Server (v. 7) freerdp-2.1.1-5.el7_9, freerdp-libs-2.1.1-5.el7_9, freerdp-libs-2.1.1-5.el7_9.ppc +2
    • Red Hat Enterprise Linux Server Optional (v. 7) freerdp-devel-2.1.1-5.el7_9, freerdp-devel-2.1.1-5.el7_9.ppc, libwinpr-devel-2.1.1-5.el7_9 +1
    • Red Hat Enterprise Linux Workstation (v. 7) freerdp-2.1.1-5.el7_9, freerdp-libs-2.1.1-5.el7_9, libwinpr-2.1.1-5.el7_9
    • Red Hat Enterprise Linux Workstation Optional (v. 7) freerdp-devel-2.1.1-5.el7_9, libwinpr-devel-2.1.1-5.el7_9
  • RHSA-2021:4623 Released 2021-11-11 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream EUS (v.8.4) freerdp-2:2.2.0-6.el8_4, freerdp-libs-2:2.2.0-6.el8_4, libwinpr-2:2.2.0-6.el8_4 +1
    • Red Hat Enterprise Linux CRB EUS (v.8.4) freerdp-devel-2:2.2.0-6.el8_4
  • RHSA-2021:4621 Released 2021-11-11 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder EUS (v. 8.2) freerdp-devel-2:2.0.0-46.rc4.el8_2.5
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) freerdp-2:2.0.0-46.rc4.el8_2.5, freerdp-libs-2:2.0.0-46.rc4.el8_2.5, libwinpr-2:2.0.0-46.rc4.el8_2.5 +1
Show 2 more Red Hat advisories
  • RHSA-2021:4622 Released 2021-11-11 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder (v. 8) freerdp-devel-2:2.2.0-7.el8_5
    • Red Hat Enterprise Linux AppStream (v. 8) freerdp-2:2.2.0-7.el8_5, freerdp-libs-2:2.2.0-7.el8_5, libwinpr-2:2.2.0-7.el8_5 +1
  • RHSA-2021:4620 Released 2021-11-11 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder EUS (v. 8.1) freerdp-devel-2:2.0.0-46.rc4.el8_1.5
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) freerdp-2:2.0.0-46.rc4.el8_1.5, freerdp-libs-2:2.0.0-46.rc4.el8_1.5, libwinpr-2:2.0.0-46.rc4.el8_1.5 +1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    FreeRDP — FEDORA-2021-2c25f03d0b

    2 records Highest priority Priority MEDIUM 2 MEDIUM

    Other records, highest priority first

    • TI-2021-17999 Improper region checks in FreeRDP allow out of bound write to memoryPriority MEDIUM 41
    Show all 2 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2021:4622
Red Hat CodeReady Linux Builder EUS (v. 8.1)Fixed RHSA-2021:4620
Red Hat CodeReady Linux Builder EUS (v. 8.2)Fixed RHSA-2021:4621
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:4622
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:4620
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:4621
Red Hat Enterprise Linux AppStream EUS (v.8.4)Fixed RHSA-2021:4623
Red Hat Enterprise Linux CRB EUS (v.8.4)Fixed RHSA-2021:4623
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:4619
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2021:4619
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:4619
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:4619
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:4619
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2021:4619
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-41159

References

Advisory 3

  • TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handling CVSS 4.0CRITICAL 9.3
  • TI-2026-85091 Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability CVSS 4.0CRITICAL 9.3
  • TI-2026-24435 FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write CVSS 3.1CRITICAL 9.8
  • TI-2023-21373 Out-Of-Bounds Write in FreeRDP CVSS 3.1CRITICAL 9.8
  • TI-2022-08692 Server side NTLM does not properly check parameters in FreeRDP CVSS 3.1CRITICAL 9.1
  • TI-2023-21374 Out-Of-Bounds Read in FreeRDP CVSS 3.1CRITICAL 9.1
See all 336 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences