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CVE-2026-55564

FreeRDP: Out-of-bounds read in glyph_cache_get via crafted glyph fragments

5.4 MediumFix available

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
Low

Exploit likelihood

0.33%Unchanged since Aug 20, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.4

FreeRDP: Out-of-bounds read in glyph_cache_get via crafted glyph fragments

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Record
CVE-2026-55564
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
Weakness
CWE-125, CWE-193
Updated
2026-11-02
EUVDEUVD-2026-62662 5.4

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Record
EUVD-2026-62662
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
Updated
2026-11-02
NVD 5.4

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Record
CVE-2026-55564
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
CVSS 3.1
7.1 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Weakness
CWE-125, CWE-193
Updated
2026-11-02
OSV 5.4

FreeRDP: Out-of-bounds read in glyph_cache_get via crafted glyph fragments

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Record
CVE-2026-55564
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
Weakness
CWE-125, CWE-193
Updated
2026-11-02
OSVDEBIAN-CVE-2026-55564 7.1

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Record
DEBIAN-CVE-2026-55564
CVSS 3.1
7.1 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-55564 5.4

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Record
UBUNTU-CVE-2026-55564
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
CVSS 3.1
7.1 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Updated
2026-11-02
OSVCLSA-2026-1791117866 No score

freerdp: Fix of 3 CVEs

  • CVE-2026-55564: fix out-of-bounds read in glyph_cache_get; reject an index equal to the cache size
  • CVE-2026-55191: fix 32-bit integer overflow in the avc444_ensure_buffer YUV444 buffer size calculation
  • CVE-2026-55192: reject H.264 frames decoded by openh264 that are smaller than the context dimensions
Record
CLSA-2026-1791117866
Updated
2026-11-02
OSVCLSA-2026-1791184271 No score

freerdp: Fix of 3 CVEs

  • CVE-2026-55564: fix out-of-bounds read in glyph_cache_get; reject an index equal to the cache size
  • CVE-2026-55191: fix 32-bit integer overflow in the avc444_ensure_buffer YUV444 buffer size calculation
  • CVE-2026-55192: reject H.264 frames decoded by openh264 that are smaller than the context dimensions
Record
CLSA-2026-1791184271
Updated
2026-11-02
OSVUSN-8561-1 No score

freerdp3 vulnerabilities

It was discovered that FreeRDP contained multiple security issues. An attacker could possibly use these issues to obtain sensitive information, cause FreeRDP to crash, resulting in a denial of service, or execute arbitrary code.

Record
USN-8561-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
freerdp
TuxCare:OracleLinux:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
freerdp-devel
TuxCare:OracleLinux:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
freerdp-libs
TuxCare:OracleLinux:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
libwinpr
TuxCare:OracleLinux:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
libwinpr-devel
TuxCare:OracleLinux:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
freerdp
TuxCare:CentOS:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
freerdp-devel
TuxCare:CentOS:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
freerdp-libs
TuxCare:CentOS:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
libwinpr
TuxCare:CentOS:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
libwinpr-devel
TuxCare:CentOS:7
From an advisory covering 3 CVEs
 before 2.1.1-5.0.9.el7_9.tuxcare.els3
2.1.1-5.0.9.el7_9.tuxcare.els3
Show 14 moreShow less
Affected packages
PackageAffectedFixed
freerdp2
Debian:12
 All versions, plus listed versions
2.10.0+dfsg1-12.10.0+dfsg1-1.12.11.2+dfsg1-12.11.2+dfsg1-1.1~exp12.11.2+dfsg1-1.1~exp2
Show 8 moreShow less
2.11.5+dfsg1-12.11.7+dfsg1-12.11.7+dfsg1-22.11.7+dfsg1-32.11.7+dfsg1-42.11.7+dfsg1-52.11.7+dfsg1-62.11.7+dfsg1-6~deb12u1
 None known
freerdp3
Debian:13
 All versions, plus listed versions
3.15.0+dfsg-2.13.15.0+dfsg-2.1+deb13u13.15.0+dfsg-2.1+deb13u23.15.0+dfsg-2.1+deb13u33.16.0+dfsg-1
Show 45 moreShow less
3.16.0+dfsg-23.17.0+dfsg-13.17.1+dfsg-13.17.1+dfsg-23.17.2+dfsg-13.17.2+dfsg-23.17.2+dfsg-33.18.0+dfsg-13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-13.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.22.0+dfsg-1~bpo13+03.22.0+dfsg-1~bpo13+13.22.0+dfsg-33.23.0+dfsg-13.23.0+dfsg-1~bpo13+13.24.0+dfsg-13.24.0+dfsg-23.24.1+dfsg-13.24.2+dfsg-13.24.2+dfsg-1~bpo13+13.25.0+dfsg-13.25.0+dfsg-23.25.0+dfsg-33.25.0+dfsg-43.25.0+dfsg-53.26.0+dfsg-13.26.0+dfsg-1~bpo13+13.27.0+dfsg-13.27.1+dfsg-13.28.0+dfsg-13.28.0+dfsg-23.29.0+dfsg-13.30.0+dfsg-13.30.0+dfsg-1~bpo13+13.31.0+dfsg-13.31.1+dfsg-13.31.1+dfsg-1~bpo13+13.32.0+dfsg-13.32.1+dfsg-13.32.1+dfsg-1~bpo13+13.32.2+dfsg-1
 None known
freerdp3
Debian:14
 before 3.27.0+dfsg-1, plus listed versions
3.15.0+dfsg-2.13.16.0+dfsg-13.16.0+dfsg-23.17.0+dfsg-13.17.1+dfsg-1
Show 28 moreShow less
3.17.1+dfsg-23.17.2+dfsg-13.17.2+dfsg-23.17.2+dfsg-33.18.0+dfsg-13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-13.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.22.0+dfsg-1~bpo13+03.22.0+dfsg-1~bpo13+13.22.0+dfsg-33.23.0+dfsg-13.23.0+dfsg-1~bpo13+13.24.0+dfsg-13.24.0+dfsg-23.24.1+dfsg-13.24.2+dfsg-13.24.2+dfsg-1~bpo13+13.25.0+dfsg-13.25.0+dfsg-23.25.0+dfsg-33.25.0+dfsg-43.25.0+dfsg-53.26.0+dfsg-13.26.0+dfsg-1~bpo13+1
3.27.0+dfsg-1
freerdp
Ubuntu:16.04:LTS
 All versions, plus listed versions
1.1.0~git20140921.1.440916e+dfsg1-5ubuntu11.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.21.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.31.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.4
 None known
freerdp2
Ubuntu:Pro:18.04:LTS
 All versions, plus listed versions
2.0.0~git20170725.1.1648deb+dfsg1-12.0.0~git20170725.1.1648deb+dfsg1-52.0.0~git20170725.1.1648deb+dfsg1-5ubuntu12.0.0~git20170725.1.1648deb+dfsg1-5ubuntu22.0.0~git20170725.1.1648deb+dfsg1-6
Show 14 moreShow less
2.0.0~git20170725.1.1648deb+dfsg1-6build12.0.0~git20170725.1.1648deb+dfsg1-72.0.0~git20170725.1.1648deb+dfsg1-7ubuntu0.12.1.1+dfsg1-0ubuntu0.18.04.12.2.0+dfsg1-0ubuntu0.18.04.12.2.0+dfsg1-0ubuntu0.18.04.22.2.0+dfsg1-0ubuntu0.18.04.32.2.0+dfsg1-0ubuntu0.18.04.42.2.0+dfsg1-0ubuntu0.18.04.4+esm12.2.0+dfsg1-0ubuntu0.18.04.4+esm22.2.0+dfsg1-0ubuntu0.18.04.4+esm32.2.0+dfsg1-0ubuntu0.18.04.4+esm42.2.0+dfsg1-0ubuntu0.18.04.4+esm52.2.0+dfsg1-0ubuntu0.18.04.4+esm6
 None known
freerdp
Ubuntu:18.04:LTS
 All versions, plus listed versions
1.1.0~git20140921.1.440916e+dfsg1-15ubuntu11.1.0~git20140921.1.440916e+dfsg1-15ubuntu1.18.04.11.1.0~git20140921.1.440916e+dfsg1-15ubuntu1.18.04.2
 None known
freerdp2
Ubuntu:Pro:20.04:LTS
 All versions, plus listed versions
2.0.0~git20190204.1.2693389a+dfsg1-12.0.0~git20190204.1.2693389a+dfsg1-22.0.0~git20190204.1.2693389a+dfsg1-2build12.0.0~git20190204.1.2693389a+dfsg1-2build22.1.1+dfsg1-0ubuntu0.20.04.1
Show 12 moreShow less
2.2.0+dfsg1-0ubuntu0.20.04.12.2.0+dfsg1-0ubuntu0.20.04.22.2.0+dfsg1-0ubuntu0.20.04.32.2.0+dfsg1-0ubuntu0.20.04.42.2.0+dfsg1-0ubuntu0.20.04.52.2.0+dfsg1-0ubuntu0.20.04.62.6.1+dfsg1-0ubuntu0.20.04.12.6.1+dfsg1-0ubuntu0.20.04.22.6.1+dfsg1-0ubuntu0.20.04.2+esm12.6.1+dfsg1-0ubuntu0.20.04.2+esm22.6.1+dfsg1-0ubuntu0.20.04.2+esm32.6.1+dfsg1-0ubuntu0.20.04.2+esm4
 None known
freerdp2
Ubuntu:22.04:LTS
 All versions, plus listed versions
2.3.0+dfsg1-2build12.3.0+dfsg1-2ubuntu12.3.0+dfsg1-2ubuntu22.4.1+dfsg1-12.4.1+dfsg1-1ubuntu1
Show 18 moreShow less
2.4.1+dfsg1-1ubuntu22.5.0+dfsg1-12.6.0+dfsg1-12.6.1+dfsg1-12.6.1+dfsg1-32.6.1+dfsg1-3ubuntu12.6.1+dfsg1-3ubuntu22.6.1+dfsg1-3ubuntu2.12.6.1+dfsg1-3ubuntu2.22.6.1+dfsg1-3ubuntu2.32.6.1+dfsg1-3ubuntu2.42.6.1+dfsg1-3ubuntu2.52.6.1+dfsg1-3ubuntu2.62.6.1+dfsg1-3ubuntu2.72.6.1+dfsg1-3ubuntu2.82.6.1+dfsg1-3ubuntu2.92.6.1+dfsg1-3ubuntu2.102.6.1+dfsg1-3ubuntu2.11
 None known
freerdp3
Ubuntu:24.04:LTS
 before 3.30.0+dfsg-0ubuntu0.24.04.1, plus listed versions
3.4.0+dfsg1-0ubuntu23.4.0+dfsg1-0ubuntu33.4.0+dfsg1-0ubuntu43.5.0+dfsg1-0ubuntu13.5.1+dfsg1-0ubuntu1
Show 5 moreShow less
3.5.1+dfsg1-0ubuntu1.13.5.1+dfsg1-0ubuntu1.23.5.1+dfsg1-0ubuntu1.43.5.1+dfsg1-0ubuntu1.53.5.1+dfsg1-0ubuntu1.6
3.30.0+dfsg-0ubuntu0.24.04.1
freerdp2
Ubuntu:Pro:24.04:LTS
 All versions, plus listed versions
2.10.0+dfsg1-1.1ubuntu12.11.2+dfsg1-12.11.2+dfsg1-1build12.11.2+dfsg1-1build32.11.5+dfsg1-1build1
Show 7 moreShow less
2.11.5+dfsg1-1build22.11.5+dfsg1-1ubuntu0.1~esm12.11.5+dfsg1-1ubuntu0.1~esm22.11.5+dfsg1-1ubuntu0.1~esm32.11.5+dfsg1-1ubuntu0.1~esm42.11.5+dfsg1-1ubuntu0.1~esm52.11.5+dfsg1-1ubuntu0.1~esm6
 None known
freerdp3
Ubuntu:25.10
 All versions, plus listed versions
3.14.0+dfsg-1ubuntu13.15.0+dfsg-2.13.16.0+dfsg-1ubuntu13.16.0+dfsg-23.16.0+dfsg-2ubuntu0.13.16.0+dfsg-2ubuntu0.33.16.0+dfsg-2ubuntu0.43.16.0+dfsg-2ubuntu0.5
 None known
freerdp3
Ubuntu:26.04:LTS
 before 3.30.0+dfsg-0ubuntu0.26.04.1, plus listed versions
3.16.0+dfsg-23.18.0+dfsg-1ubuntu13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-1
Show 6 moreShow less
3.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.24.1+dfsg-1ubuntu13.24.2+dfsg-1ubuntu13.24.2+dfsg-1ubuntu1.1
3.30.0+dfsg-0ubuntu0.26.04.1
freerdp3
Ubuntu:24.04:LTS
From an advisory covering 34 CVEs
 before 3.30.0+dfsg-0ubuntu0.24.04.1, plus listed versions
3.4.0+dfsg1-0ubuntu23.4.0+dfsg1-0ubuntu33.4.0+dfsg1-0ubuntu43.5.0+dfsg1-0ubuntu13.5.1+dfsg1-0ubuntu1
Show 5 moreShow less
3.5.1+dfsg1-0ubuntu1.13.5.1+dfsg1-0ubuntu1.23.5.1+dfsg1-0ubuntu1.43.5.1+dfsg1-0ubuntu1.53.5.1+dfsg1-0ubuntu1.6
3.30.0+dfsg-0ubuntu0.24.04.1
freerdp3
Ubuntu:26.04:LTS
From an advisory covering 34 CVEs
 before 3.30.0+dfsg-0ubuntu0.26.04.1, plus listed versions
3.16.0+dfsg-23.18.0+dfsg-1ubuntu13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-1
Show 6 moreShow less
3.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.24.1+dfsg-1ubuntu13.24.2+dfsg-1ubuntu13.24.2+dfsg-1ubuntu1.1
3.30.0+dfsg-0ubuntu0.26.04.1

History

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

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

In short

CVE-2026-55564 is a medium vulnerability (CVSS 5.4) in Freerdp, published July 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 26th percentile. Fixed in freerdp3 3.27.0+dfsg-1.

References

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