CVE-2026-64620: FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfre

Q: How do I fix CVE-2026-64620?

freerdp: upgrade to 3.28.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-64620 being exploited?

CVE-2026-64620 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-64620 affect?

CVE-2026-64620 affects freerdp. Severity is critical (CVSS 9.8). FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and o

Q: How urgent is CVE-2026-64620?

Priority 62/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-64620 is a critical-severity flaw (CVSS 9.8) affecting freerdp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length > out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decry

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 40%)
CISA exploited list	No
Weakness	CWE-122
Published	2026-07-20
Last modified	2026-07-28

Publisher (CNA): VulnCheck · Vendor: freerdp

Last updated 2026-07-28 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-20 12:19 UTCPublished CVE record published
2026-07-28 15:38 UTCUpdated Record last modified

freerdp freerdp UPGRADE

Affected: < 3.28.0

Fixed in: 3.28.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 3.28.0 (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.

Exact fixes by distribution

Fedora 46 · gcl · FIXED · 2.7.1-12.fc46 · FEDORA-2026-ff383a759b · source

sudo dnf upgrade --advisory=FEDORA-2026-ff383a759b

Fedora ELN · mozjs140 · FIXED · 140.13.0-5.eln159 · FEDORA-2026-f7ed0026e0 · source

sudo dnf upgrade --advisory=FEDORA-2026-f7ed0026e0

Ubuntu 24.04 · freerdp3 · FIXED · 3.30.0+dfsg-0ubuntu0.24.04.1

sudo apt update && sudo apt install --only-upgrade freerdp3 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' freerdp3)" ge "3.30.0+dfsg-0ubuntu0.24.04.1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · freerdp2 · NO FIX YET

Debian 13 · freerdp3 · NO FIX YET

RHEL 10 · freerdp · FIXED · freerdp-3.10.3-12.el10_2.8

sudo dnf upgrade --advisory=RHSA-2026:54486 rpm -q freerdp

RHEL 10.0 Extended Update Support · freerdp · FIXED · freerdp-3.10.3-3.el10_0.11

sudo dnf upgrade --advisory=RHSA-2026:58711 rpm -q freerdp

RHEL 6 · freerdp · DEFERRED

RHEL 7 · freerdp · NOT AFFECTED

RHEL 8 · freerdp · NOT AFFECTED

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2053 · source

sudo dnf update --advisory=ALAS2023-2026-2053

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pjqx-v446-x7fc

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-2026-64620?

freerdp: upgrade to 3.28.0. Exact commands for each OS are on this page.

Is CVE-2026-64620 being exploited?

CVE-2026-64620 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-2026-64620 affect?

CVE-2026-64620 affects freerdp. Severity is critical (CVSS 9.8). FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and o

How urgent is CVE-2026-64620?

Priority 62/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

WinRM and RDP vulnerabilities

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References

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