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TI-2026-18350 Aliases CVE-2026-22858

FreeRDP has a global-buffer-overflow in crypto_base64_decode

Priority MEDIUM 58CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
High
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Partial Red Hat: 24 fixed, 1 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00703 53rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial FreeRDP (FreeRDP): 3.20.1Red Hat: 14 advisoriesRed Hat: 24 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FreeRDPFreeRDPbefore 3.20.13.20.1Patch availableCNA
  • FreeRDP VendorFreeRDP Affected before 3.20.1 Fixed in 3.20.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*before 3.20.1VulnerableFreeRDP
  • cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* Versions before 3.20.1 Vulnerable ·FreeRDP

Remediation

  • Fix · CNA FreeRDP (FreeRDP) Fixed in 3.20.1

Red Hat 14 advisories

  • RHSA-2026:19033 Released 2026-05-19 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 10) freerdp-2:3.10.3-12.el10_2.2, freerdp-libs-2:3.10.3-12.el10_2.2, libwinpr-2:3.10.3-12.el10_2.2
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-devel-2:3.10.3-12.el10_2.2, freerdp-server-2:3.10.3-12.el10_2.2, libwinpr-devel-2:3.10.3-12.el10_2.2
  • RHSA-2026:4489 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.0) freerdp-2:2.4.1-3.el9_0.1, freerdp-libs-2:2.4.1-3.el9_0.1, libwinpr-2:2.4.1-3.el9_0.1
  • RHSA-2026:4471 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux Server (v. 7 ELS) freerdp-2.1.1-5.el7_9.2, freerdp-libs-2.1.1-5.el7_9.2, freerdp-libs-2.1.1-5.el7_9.2.ppc +2
    • Red Hat Enterprise Linux Server Optional (v. 7 ELS) freerdp-devel-2.1.1-5.el7_9.2, freerdp-devel-2.1.1-5.el7_9.2.ppc, libwinpr-devel-2.1.1-5.el7_9.2 +1
Show 11 more Red Hat advisories
  • RHSA-2026:4446 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.6) freerdp-2:2.2.0-7.el8_6.2, freerdp-libs-2:2.2.0-7.el8_6.2, libwinpr-2:2.2.0-7.el8_6.2 +1
    • Red Hat Enterprise Linux AppStream E4S (v.8.6) freerdp-2:2.2.0-7.el8_6.2, freerdp-libs-2:2.2.0-7.el8_6.2, libwinpr-2:2.2.0-7.el8_6.2 +1
    • Red Hat Enterprise Linux AppStream TUS (v.8.6) freerdp-2:2.2.0-7.el8_6.2, freerdp-libs-2:2.2.0-7.el8_6.2, libwinpr-2:2.2.0-7.el8_6.2 +1
  • RHSA-2026:4440 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream E4S (v.8.8) freerdp-2:2.2.0-12.el8_8.2, freerdp-libs-2:2.2.0-12.el8_8.2, libwinpr-2:2.2.0-12.el8_8.2 +1
    • Red Hat Enterprise Linux AppStream TUS (v.8.8) freerdp-2:2.2.0-12.el8_8.2, freerdp-libs-2:2.2.0-12.el8_8.2, libwinpr-2:2.2.0-12.el8_8.2 +1
  • RHSA-2026:4438 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder EUS (v.9.4) freerdp-devel-2:2.11.2-1.el9_4.2, libwinpr-devel-2:2.11.2-1.el9_4.2
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) freerdp-2:2.11.2-1.el9_4.2, freerdp-libs-2:2.11.2-1.el9_4.2, libwinpr-2:2.11.2-1.el9_4.2
  • RHSA-2026:4439 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.4) freerdp-2:2.2.0-8.el8_4, freerdp-libs-2:2.2.0-8.el8_4, libwinpr-2:2.2.0-8.el8_4 +1
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) freerdp-2:2.2.0-8.el8_4, freerdp-libs-2:2.2.0-8.el8_4, libwinpr-2:2.2.0-8.el8_4 +1
  • RHSA-2026:4437 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) freerdp-2:2.4.1-6.el9_2.3, freerdp-libs-2:2.4.1-6.el9_2.3, libwinpr-2:2.4.1-6.el9_2.3
  • RHSA-2026:4433 Released 2026-03-12 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream AUS (v. 8.2) freerdp-2:2.0.0-46.rc4.el8_2.7, freerdp-libs-2:2.0.0-46.rc4.el8_2.7, libwinpr-2:2.0.0-46.rc4.el8_2.7 +1
  • RHSA-2026:4121 Released 2026-03-09 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) freerdp-2:3.10.3-3.el10_0.2, freerdp-libs-2:3.10.3-3.el10_0.2, libwinpr-2:3.10.3-3.el10_0.2
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) freerdp-devel-2:3.10.3-3.el10_0.2, freerdp-server-2:3.10.3-3.el10_0.2, libwinpr-devel-2:3.10.3-3.el10_0.2
  • RHSA-2026:3975 Released 2026-03-09 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) freerdp-devel-2:2.11.7-1.el9_6.2, libwinpr-devel-2:2.11.7-1.el9_6.2
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) freerdp-2:2.11.7-1.el9_6.2, freerdp-libs-2:2.11.7-1.el9_6.2, libwinpr-2:2.11.7-1.el9_6.2
  • RHSA-2026:3334 Released 2026-02-25 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 8) freerdp-2:2.11.7-3.el8_10, freerdp-libs-2:2.11.7-3.el8_10, libwinpr-2:2.11.7-3.el8_10 +1
    • Red Hat Enterprise Linux CRB (v. 8) freerdp-devel-2:2.11.7-3.el8_10
  • RHSA-2026:3067 Released 2026-02-23 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 9) freerdp-2:2.11.7-1.el9_7.2, freerdp-libs-2:2.11.7-1.el9_7.2, libwinpr-2:2.11.7-1.el9_7.2
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) freerdp-devel-2:2.11.7-1.el9_7.2, libwinpr-devel-2:2.11.7-1.el9_7.2
  • RHSA-2026:3068 Released 2026-02-23 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 10) freerdp-2:3.10.3-5.el10_1.2, freerdp-libs-2:3.10.3-5.el10_1.2, libwinpr-2:3.10.3-5.el10_1.2
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-devel-2:3.10.3-5.el10_1.2, freerdp-server-2:3.10.3-5.el10_1.2, libwinpr-devel-2:3.10.3-5.el10_1.2

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Will not fix
Red Hat CodeReady Linux Builder EUS (v.9.4)Fixed RHSA-2026:4438
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:3975
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:19033, RHSA-2026:3068
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:3334
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:3067
Red Hat Enterprise Linux AppStream AUS (v. 8.2)Fixed RHSA-2026:4433
Red Hat Enterprise Linux AppStream AUS (v.8.4)Fixed RHSA-2026:4439
Red Hat Enterprise Linux AppStream AUS (v.8.6)Fixed RHSA-2026:4446
Red Hat Enterprise Linux AppStream E4S (v.8.6)Fixed RHSA-2026:4446
Red Hat Enterprise Linux AppStream E4S (v.8.8)Fixed RHSA-2026:4440
Red Hat Enterprise Linux AppStream E4S (v.9.0)Fixed RHSA-2026:4489
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:4437
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:4121
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2026:4438
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:3975
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)Fixed RHSA-2026:4439
Red Hat Enterprise Linux AppStream TUS (v.8.6)Fixed RHSA-2026:4446
Red Hat Enterprise Linux AppStream TUS (v.8.8)Fixed RHSA-2026:4440
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:3334
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:19033, RHSA-2026:3068
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:3067
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:4121
Red Hat Enterprise Linux Server (v. 7 ELS)Fixed RHSA-2026:4471
Red Hat Enterprise Linux Server Optional (v. 7 ELS)Fixed RHSA-2026:4471

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-22858

References

Exploit 1

Other 1

  • TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handling CVSS 4.0CRITICAL 9.3
  • TI-2026-85091 Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability CVSS 4.0CRITICAL 9.3
  • TI-2026-24435 FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write CVSS 3.1CRITICAL 9.8
  • TI-2023-21373 Out-Of-Bounds Write in FreeRDP CVSS 3.1CRITICAL 9.8
  • TI-2022-08692 Server side NTLM does not properly check parameters in FreeRDP CVSS 3.1CRITICAL 9.1
  • TI-2023-21374 Out-Of-Bounds Read in FreeRDP CVSS 3.1CRITICAL 9.1
See all 336 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences