CVE-2026-109939: FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in lib

Routine

MEDIUM 6.5UPGRADE

CVE-2026-109939 is a medium-severity flaw (CVSS 6.5) affecting freerdp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in libfreerdp/core/orders.c, which accesses the client bitmap cache when the CBR3_DO_NOT_CACHE flag is set, even though the cache is not yet initialized before Demand Active. A malicious or compromised RDP server can send a Cache Bitmap V3 order during connection setup to crash a connecting client that has enabled the non-default Bitmap Cache V

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-476
Published	2026-10-13
Last modified	2026-10-26

Publisher (CNA): VulnCheck · Vendor: freerdp

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-13 14:17 UTCPublished CVE record published
2026-10-26 20:29 UTCUpdated Record last modified

freerdp freerdp UPGRADE

Affected: >= 3.27.1 and < 3.32.0

Fixed in: 3.32.0

Safe to downgrade to: a release before 3.27.1

1. Check installed version

apt-cache policy freerdp || rpm -q freerdp || freerdp --version

2. UPGRADE to 3.32.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freerdp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freerdp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.27.1 (Debian / Ubuntu)

apt-cache madison freerdp sudo apt install freerdp=<VERSION_BEFORE_3.27.1> sudo apt-mark hold freerdp

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freerdp sudo dnf downgrade freerdp-<VERSION_BEFORE_3.27.1> sudo dnf versionlock add freerdp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-109939?

freerdp: upgrade to 3.32.0. Exact commands for each OS are on this page.

Is CVE-2026-109939 being exploited?

CVE-2026-109939 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-109939 affect?

CVE-2026-109939 affects freerdp. Severity is medium (CVSS 6.5). FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in libfreerdp/core/orders.c, which accesses the client bitmap cache when the CBR3_DO_NOT_CACHE flag is set, even though the cache is not

How urgent is CVE-2026-109939?

Priority 33/100. Public exploit reference

Software pages

WinRM and RDP vulnerabilities

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References

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