NVD / CVE Program· CNA GitHub_M

CVE-2020-4031: Use-After-Free in gdi_SelectObject in FreeRDP

Noroxi assessment

Priority: Monitor (action score 30/100)

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: 1.6% (FIRST EPSS); higher than 75.8% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: FreeRDP FreeRDP 2.1.2.
Severity is disputed: the assigning authority (CNA) scores it 3.5, NVD 7.5.

Low priority for now. Upgrade to FreeRDP FreeRDP 2.1.2 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

In FreeRDP before version 2.1.2, there is a use-after-free in gdi_SelectObject. All FreeRDP clients using compatibility mode with /relax-order-checks are affected. This is fixed in version 2.1.2.

HighCVSS 7.5 · v3.1—No exploit Fix available

BDU:2021-01349

Published: Jun 22, 2020
Updated: Jun 16, 2026
EPSS: 1.6% · 75th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 1.6%

CNA vs NVD score

NVD: 7.5
CNA · GitHub_M: 3.5; 4.0 point gap

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

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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.

Vendor	Product	CPE
freerdp	freerdp	cpe:2.3:a:freerdp:freerdp
fedoraproject	fedora	cpe:2.3:o:fedoraproject:fedora
opensuse	leap	cpe:2.3:o:opensuse:leap
canonical	ubuntu linux	cpe:2.3:o:canonical:ubuntu_linux
debian	debian linux	cpe:2.3:o:debian:debian_linux

Affected versions

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

canonical ubuntu linux18.04
canonical ubuntu linux20.04
debian debian linux10.0
fedoraproject fedora31
fedoraproject fedora32
freerdp freerdpbefore 2.1.2
opensuse leap15.1

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
- < 2.1.2affected

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	freerdp2	before 2.1.2+dfsg1-1	2.1.2+dfsg1-1

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 gdi_Bitmap_Decompress
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 co
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 update_read_bitmap_
41Plan

Published before and after this one in the same product

← EarlierCVE-2020-11099Jun 22, 2020 · OOB Read in license_read_new_or_upgrade_license_packet in FreeRDP
27Monitor
← EarlierCVE-2020-4030Jun 22, 2020 · OOB read in `TrioParse` in FreeRDP
26Monitor
Later →CVE-2020-4032Jun 22, 2020 · Integer casting vulnerability in `update_recv_secondary_order` in FreeRDP
18Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
FreeRDP FreeRDP	2.1.2 · description	Vendor (CNA)
debian:freerdp2	2.1.2+dfsg1-1 · Debian:12	Package 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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

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

FreeRDP/FreeRDPcommit 6d86e20

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

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

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

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

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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.

Change log

Fix✗ → ✓Sep 28, 2026, 10:48 PM UTC

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References

lists.opensuse.org/opensuse-security-announce/2020-07/msg00080.html

Show all references (7 more)

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

All records