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CVE-2026-55238

xrdp: Malformed Confirm Active capability sets cause out-of-bounds reads

5.3 MediumFix available

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.52%Unchanged since Jul 21, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

xrdp: Malformed Confirm Active capability sets cause out-of-bounds reads

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Record
CVE-2026-55238
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-126
Updated
2026-11-02
EUVDEUVD-2026-46036 5.3

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Record
EUVD-2026-46036
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
NVD 5.3

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Record
CVE-2026-55238
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-126
Updated
2026-11-02
OSV 5.3

xrdp: Malformed Confirm Active capability sets cause out-of-bounds reads

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Record
CVE-2026-55238
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-126
Updated
2026-11-02
OSVDEBIAN-CVE-2026-55238 5.3

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Record
DEBIAN-CVE-2026-55238
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVUBUNTU-CVE-2026-55238 5.3

xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.

Record
UBUNTU-CVE-2026-55238
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVMGASA-2026-0566 No score

Updated xrdp package fixes security vulnerabilities

lib_palette_update Heap Buffer Overflow & RCE. (CVE-2026-41252) lib_framebuffer_update Has Integer Overflow Heap Info Leak & ASLR Bypass. (CVE-2026-41521) Channel Data Forwarding Fixed-Size Buffer Overflow. (CVE-2026-44178) XRDP is vulnerable to a server timing attack, leading to user enumeration. (CVE-2026-42218) Unchecked FIPS padding length in standard RDP Security causes heap out-of-bounds read in HMAC verification. (CVE-2026-44978) Pre-auth infinite loop via totalLength=0 in TS_SHARECONTROLHEADER. (CVE-2026-54538) Malformed Confirm Active capability sets cause out-of-bounds reads. (CVE-2026-55238) No authentication required with Xvnc backend. (CVE-2026-55626) Out-of-bounds read in GCC Conference Create Request CS_SECURITY processing (xrdp_sec_process_mcs_data_CS_SECURITY). (CVE-2026-55639) Out-of-bounds read in Client Control PDU processing (xrdp_rdp_process_data_control). (CVE-2026-55645)

Record
MGASA-2026-0566
Updated
2026-11-02
OSVopenSUSE-SU-2026:11543-1 No score

xrdp-0.10.6.1-1.1 on GA media

These are all security issues fixed in the xrdp-0.10.6.1-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11543-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
xrdp
Debian:12
before 0.9.21.1-1+deb12u3, plus listed versions
0.9.21.1-10.9.21.1-1+deb12u10.9.21.1-1+deb12u2
0.9.21.1-1+deb12u3
xrdp
Debian:13
before 0.10.1-3.1+deb13u2, plus listed versions
0.10.1-3.10.10.1-3.1+deb13u1
0.10.1-3.1+deb13u2
xrdp
Debian:14
before 0.10.6.1-2, plus listed versions
0.10.1-3.10.10.1-40.10.1-4.10.10.2-10.10.2-2
Show 14 moreShow less
0.10.4.1-10.10.4.1-20.10.5-10.10.5-20.10.5-30.10.5-40.10.5-50.10.6-10.10.6-20.10.6-30.10.6-40.10.6-50.10.6.1-10.10.6.1-2~bpo13+1
0.10.6.1-2
xrdp
Mageia:10
From an advisory covering 10 CVEs
before 0.10.6.1-2.mga10
0.10.6.1-2.mga10
xrdp
Ubuntu:Pro:14.04:LTS
All versions, plus listed versions
0.6.0-10.6.0-1ubuntu0.10.6.0-1ubuntu0.1+esm10.6.0-1ubuntu0.1+esm20.6.0-1ubuntu0.1+esm3
None known
xrdp
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
0.6.1-20.6.1-2ubuntu0.10.6.1-2ubuntu0.30.6.1-2ubuntu0.3+esm10.6.1-2ubuntu0.3+esm20.6.1-2ubuntu0.3+esm3
None known
xrdp
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
0.9.1-90.9.4-10.9.4-20.9.4-30.9.4-4
Show 7 moreShow less
0.9.4-50.9.5-10.9.5-1build10.9.5-20.9.5-2ubuntu0.1~esm10.9.5-2ubuntu0.1~esm20.9.5-2ubuntu0.1~esm3
None known
xrdp
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
0.9.9-10.9.12-10.9.12-1ubuntu0.10.9.12-1ubuntu0.1+esm10.9.12-1ubuntu0.1+esm2
None known
xrdp
Ubuntu:22.04:LTS
All versions, plus listed versions
0.9.15-1ubuntu10.9.17-10.9.17-20.9.17-2ubuntu10.9.17-2ubuntu2
Show 5 moreShow less
0.9.17-2ubuntu2+esm10.9.17-2ubuntu30.9.17-2ubuntu3+esm10.9.17-2ubuntu3+esm20.9.17-2ubuntu3.1
None known
xrdp
Ubuntu:24.04:LTS
All versions, plus listed versions
0.9.21.1-10.9.24-20.9.24-30.9.24-3build10.9.24-3build20.9.24-40.9.24-4ubuntu0.1~esm10.9.24-4ubuntu0.1
None known
Show 4 moreShow less
Affected packages
PackageAffectedFixed
xrdp
Ubuntu:25.10
All versions, plus listed versions
0.10.1-30.10.1-3.10.10.1-3.1+deb13u1build0.25.10.1
None known
xrdp
Ubuntu:26.10
All versions, plus listed versions
0.10.1-4.10.10.6.1-2ubuntu1
None known
xrdp
Ubuntu:26.04:LTS
All versions, plus listed versions
0.10.1-3.10.10.1-40.10.1-4.10.10.1-4.1ubuntu0.1
None known
xrdp
openSUSE:Tumbleweed
From an advisory covering 10 CVEs
before 0.10.6.1-1.1
0.10.6.1-1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-55238 is a medium vulnerability (CVSS 5.3) in Neutrinolabs Xrdp, published July 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.52%, the 44th percentile. Fixed in xrdp 0.9.21.1-1+deb12u3.

References

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