Freerdp Freerdp
CVE-2026-85089
FreeRDP versions 3.0.0 through 3.30.0 (before 3.31.0) transmit uninitialized heap memory in Save Session Info PDU reserved padding fields. Three PDU writers in libfreerdp/core/info.c (rdp_write_logon_info_v2, rdp_write_logon_info_plain, and rdp_write_logon_info_ex) use Stream_Seek instead of Stream_Zero for reserved pad bytes (up to 576 bytes), leaving previously freed heap contents in the outgoing PDU. Because the send buffer is allocated with malloc (not zeroed), stale heap data — which may include cleartext credentials from prior sessions — can be sent to the receiving peer. FreeRDP-based servers using rdpUpdate::SaveSessionInfo and freerdp-proxy (which forwards these PDUs) are affected, allowing disclosure of server/proxy process memory to a downstream client.
What this means for your business
- It affects Freerdp. It matters if your company, or a supplier that handles your data, runs it.
- Code showing how to exploit it has been published, but real attacks have not been confirmed.
- An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 35% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Freerdp, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
Not sure if your company is exposed to CVE-2026-85089?
Tell us where you run Freerdp Freerdp and a Fastnexa penetration tester will check whether this flaw, or others like it, can be used against your websites, apps and network.
The full test is free for our first 10 founding clients until 31 December 2026. See the offer
Think you’ve already been hit? Don’t wait on a form: call or WhatsApp +1 (732) 454 2616. We reply within 1 hour, 24/7. Emergency help →
Scoring
- CVSS
- 6.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N- CVSS v4
- 7.1
- Weakness
- CWE-908
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-03
- Last modified
- 2026-09-09
- Sources
- NVD
Affected products
- Freerdp Freerdp3.0.0 - 3.31.0
As listed in the NVD configuration data. Not a statement about your estate.
References
- https://github.com/FreeRDP/FreeRDP
- https://github.com/FreeRDP/FreeRDP/blob/3.30.0/libfreerdp/core/info.c#L1541
- https://github.com/FreeRDP/FreeRDP/commit/056cede398d71c1f2540baebc26ec3327a249301
- https://github.com/FreeRDP/FreeRDP/commit/483c9388119f06bac420d92053cff9ef94e83bea
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.31.0
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-v649-94v2-p72q
- https://www.vulncheck.com/advisories/freerdp-before-3.31.0-information-disclosure-via-uninitialized-heap-memory
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-v649-94v2-p72q