{"id":"CVE-2026-26955","summary":"FreeRDP has Out-of-bounds Write","details":"FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, a malicious RDP server can trigger a heap buffer overflow in FreeRDP clients using the GDI surface pipeline (e.g., `xfreerdp`) by sending an RDPGFX ClearCodec surface command with an out-of-bounds destination rectangle. The `gdi_SurfaceCommand_ClearCodec()` handler does not call `is_within_surface()` to validate the command rectangle against the destination surface dimensions, allowing attacker-controlled `cmd-\u003eleft`/`cmd-\u003etop` (and subcodec rectangle offsets) to reach image copy routines that write into `surface-\u003edata` without bounds enforcement. The OOB write corrupts an adjacent `gdiGfxSurface` struct's `codecs*` pointer with attacker-controlled pixel data, and corruption of `codecs*` is sufficient to reach an indirect function pointer call (`NSC_CONTEXT.decode` at `nsc.c:500`) on a subsequent codec command — full instruction pointer (RIP) control demonstrated in exploitability harness. Users should upgrade to version 3.23.0 to receive a patch.","aliases":["GHSA-mr6w-ch7c-mqqj"],"modified":"2026-08-18T18:38:56.154160Z","published":"2026-02-25T20:47:14.660Z","related":["ALSA-2026:5939","ALSA-2026:6004","ALSA-2026:6005","SUSE-SU-2026:1129-1","SUSE-SU-2026:1160-1","SUSE-SU-2026:1164-1","SUSE-SU-2026:1165-1","SUSE-SU-2026:1398-1","SUSE-SU-2026:21436-1","openSUSE-SU-2026:10408-1","openSUSE-SU-2026:10459-1","openSUSE-SU-2026:20632-1","openSUSE-SU-2026:20657-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26955.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-787"]},"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26955.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:19033"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:5936"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:5939"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6004"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6005"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6384"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6385"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6395"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6396"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6616"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6665"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6712"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6764"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:7292"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-26955"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26955.json"},{"type":"ADVISORY","url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-mr6w-ch7c-mqqj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26955"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2443132"},{"type":"FIX","url":"https://github.com/FreeRDP/FreeRDP/commit/7d8fdce2d0ef337cb86cb37fc0c436c905e04d77"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/freerdp/freerdp","events":[{"introduced":"0"},{"fixed":"b933ae18d9ad2a1d73c610868fcc30eb61654070"},{"fixed":"7d8fdce2d0ef337cb86cb37fc0c436c905e04d77"}],"database_specific":{"cpe":"cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"3.23.0"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["3.5.1","3.5.0","3.4.0","3.3.0","3.2.0","3.1.0","3.0.0","3.0.0-rc0","3.0.0-beta4","3.0.0-beta3","3.0.0-beta2","3.0.0-beta1","2.0.0","2.0.0-rc4","2.0.0-rc3","2.0.0-rc2","2.0.0-rc1","2.0.0-rc0","2.0.0-beta1+android11","2.0.0-beta1+android10","1.2.0-beta1+android9","1.2.0-beta1+android7","1.1.0-beta+2013071101","1.1.0-beta1+ios4","1.1.0-beta1+android5","1.1.0-beta1+android4","1.1.0-beta1+ios3","1.1.0-beta1+ios2","1.1.0-beta1+android3","1.1.0-beta1+android2","1.1.0-beta1+ios1","1.1.0-beta1","1.0.1","1.0.0","1.0-beta5","1.0-beta4","1.0-beta2","1.0-beta1"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-26955.json","vanir_signatures_modified":"2026-08-18T18:38:56Z","vanir_signatures":[{"id":"CVE-2026-26955-3b6c30c0","signature_type":"Line","signature_version":"v1","source":"https://github.com/freerdp/freerdp/commit/7d8fdce2d0ef337cb86cb37fc0c436c905e04d77","target":{"file":"libfreerdp/codec/clear.c"},"deprecated":false,"digest":{"threshold":0.9,"line_hashes":["337102543481686678806426411982219186725","142178338594568985456747912589820267684","321241827299255414039213524635076784854","191482064253101754193482270492063537284","313014913062463781557687446026456019312","225939152721285012853400641492428312768","157778159804837661293442588007063628225","249096992896262465669941567909039340523","118305146628341557657848518247870006318","72464142610846638201591829741155265446","266547187582236839130398311058964394112","109286712232311739019943485516455006562","16373416886167172447552647924719246384"]}}]}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}