VulnerabilityPublished 9 Jul 2026Updated 23 Sep 2026

CVE-2026-55564: libfreerdp/cache/glyph.c checks whether index · Prior to 3.27.0, the glyph_cache_get function

Affects freerdpSource GCVE Database

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Authoritative record:CVE-2026-55564· Medium 5.4

Not known to be exploited · CVSS 5.4 Medium · fixed in 3.30.0+dfsg-0ubuntu0.24.04.1 : update freerdp when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

5.4Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.30.0+dfsg-0ubuntu0.24.04.1, 3.30.0+dfsg-0ubuntu0.26.04.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade the Ubuntu freerdp3 to 3.30.0+dfsg-0ubuntu0.24.04.1 (package) or 3.30.0+dfsg-0ubuntu0.26.04.1 (package).

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSfreerdp3`pkg:deb/ubuntu/freerdp3?arch=source&distro=resolute`Other threats	Affected <3.30.0+dfsg-0ubuntu0.26.04.1	Fixed in 3.30.0+dfsg-0ubuntu0.26.04.1
Ubuntu 25.10freerdp3`pkg:deb/ubuntu/freerdp3?arch=source&distro=questing`Other threats	Affected 3.14.0+dfsg-1ubuntu1 – 3.16.0+dfsg-2ubuntu0.5 8 affected builds	Fixed in–
Ubuntu 24.04 LTSfreerdp3`pkg:deb/ubuntu/freerdp3?arch=source&distro=noble`Other threats	Affected <3.30.0+dfsg-0ubuntu0.24.04.1	Fixed in 3.30.0+dfsg-0ubuntu0.24.04.1
Ubuntu Pro 24.04 LTSfreerdp2`pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-apps/noble`Other threats	Affected 2.10.0+dfsg1-1.1ubuntu1 – 2.11.5+dfsg1-1ubuntu0.1~esm6 12 affected builds	Fixed in–
Ubuntu 22.04 LTSfreerdp2`pkg:deb/ubuntu/freerdp2?arch=source&distro=jammy`Other threats	Affected 2.3.0+dfsg1-2build1 – 2.6.1+dfsg1-3ubuntu2.11 23 affected builds	Fixed in–
Ubuntu Pro 20.04 LTSfreerdp2`pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-infra/focal`Other threats	Affected 2.0.0~git20190204.1.2693389a+dfsg1-1 – 2.6.1+dfsg1-0ubuntu0.20.04.2+esm4 17 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available that fixes this vulnerability in FreeRDP version 3.27.0. Users and administrators should update to version 3.27.0 or later to remediate this issue. Standard system updates on supported Ubuntu releases will apply the necessary fixes. No additional mitigations are required once the update is applied.

Description

FreeRDP versions prior to 3.27.0 contain a vulnerability in the glyph_cache_get function where an off-by-one error allows reading beyond the bounds of an array. This flaw can be triggered by a malicious RDP server causing the client to dereference memory adjacent to the glyph cache, potentially leading to a crash and limited disclosure of adjacent heap data. The issue is fixed in FreeRDP version 3.27.0.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Sep 2026, 08:22 UTC

Technical details

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