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CVE-2026-22858Proof of concept (PoC) published · CISA

FreeRDP has a global-buffer-overflow in crypto_base64_decode

CVSS score

5.6

EPSS probability

%0.7

Risk score

0.0

Published

9 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

Impact on My Inventory

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-22858 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, global-buffer-overflow was observed in FreeRDP's Base64 decoding path. The root cause appears to be implementation-defined char signedness: on Arm/AArch64 builds, plain char is treated as unsigned, so the guard c <= 0 can be optimized into a simple c != 0 check. As a result, non-ASCII bytes (e.g., 0x80-0xFF) may bypass the intended range restriction and be used as an index into a global lookup table, causing out-of-bounds access. This vulnerability is fixed in 3.20.1.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-22858 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1freerdpfreerdp View
2freerdpfreerdp View
Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.1CVSS V31CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HNVD
7.4CVSS V31HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:HNVD
7.4CVSS V3_1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:HCVE ADP
5.6CVSS V40MEDIUMCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XNVD
5.6CVSS V4_0MEDIUMCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:PCVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

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Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-22858 is associated with the following CWEs:

CWE-125: Out-of-bounds ReadCWE-758: Common Weakness Enumeration Entry CWE-758CWE-787: Out-of-bounds Write

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-22858 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
User—

Official Sources and Advisories

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896vendor-advisoryhttps://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1vendor-advisoryhttps://access.redhat.com/errata/RHSA-2026:19033nvdhttps://access.redhat.com/errata/RHSA-2026:3067nvdhttps://access.redhat.com/errata/RHSA-2026:3068nvdhttps://access.redhat.com/errata/RHSA-2026:3334nvdhttps://access.redhat.com/errata/RHSA-2026:3975nvdhttps://access.redhat.com/errata/RHSA-2026:4121nvdhttps://access.redhat.com/errata/RHSA-2026:4433nvdhttps://access.redhat.com/errata/RHSA-2026:4437nvd

CVSS Vector Radar Chart

5.6 / 10
Attack VectorNetworkComplexityHighPrivilegesNoneUser Interact.RequiredConfidentialityHighIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone required
User InteractionP
Confidentiality (Gizlilik)High
Integrity (Bütünlük)P
Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

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Weakness Type (CWE & CAPEC)

CWE-125 CWE-758 CWE-787

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