CVE-2026-40033

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-26. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: Elevated riskExposed: 0

A fix is available — apply it.

FreeRDP before 3.26.0 contains a heap-buffer-overflow vulnerability in gdi_CacheToSurface that allows remote attackers to write out-of-bounds heap memory. The vulnerability occurs because rectangle validation clamps coordinates to UINT16_MAX but performs copy operations using unclamped cache entry dimensions, enabling malicious RDP servers to trigger large out-of-bounds writes and potentially achieve remote code execution or client crash.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
56(Track*)
EG Risk 56/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
1%
EPSS %ILE
62%
KEV
Not listed

Published

May 26, 2026

Last Modified

July 27, 2026

Advisory Details (3)

Auto-updated Jun 2, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff
generic

FreeRDP - Heap-buffer-overflow in gdi_CacheToSurface via rectangle validation bypass | Advisories | VulnCheck

https://www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-in-gdi-cachetosurface-via-rectangle-validation-bypass
github_commit

commit 23b36cd00ebf (FreeRDP/FreeRDP)

Fix landed in FreeRDP/FreeRDP commit 23b36cd00ebf — awaiting tagged release

https://github.com/FreeRDP/FreeRDP/commit/23b36cd00ebf0ccd97750fcdbc9aa2f362352da7

Vendor Advisories for CVE-2026-40033(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuwinpr3-utils (3.30.0+dfsg-0ubuntu0.26.04.1) @ resolute2026-08-23ubuntu
redhatfreerdp-2:3.10.3-3.el10_0.92026-07-27redhat
redhatfreerdp-2:3.10.3-12.el10_2.62026-07-07redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
freerdp22.10.0+dfsg1-1 ... 2.9.0+dfsg1-1~bpo11+1 (32 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
freerdp22.10.0+dfsg1-1 ... 2.11.7+dfsg1-6~deb12u1 (13 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
freerdp33.15.0+dfsg-2.1 ... 3.31.0+dfsg-1 (44 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
freerdp33.15.0+dfsg-2.1 ... 3.26.0+dfsg-1~bpo13+1 (32 versions)3.26.0+dfsg-1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 37× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 274 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 03:11 UTCEPSS rescore
  7. 2026-09-13 16:47 UTCEPSS rescore
  8. 2026-09-12 15:01 UTCEPSS rescore
  9. 2026-09-11 14:53 UTCEPSS rescore
  10. 2026-09-11 09:37 UTCEPSS rescore
  11. 2026-09-11 01:53 UTCOSV refresh
  12. 2026-09-10 09:34 UTCEPSS rescore
  13. 2026-09-08 22:00 UTCEPSS rescore
  14. 2026-09-07 16:01 UTCEPSS rescore
  15. 2026-09-06 13:47 UTCEPSS rescore
  16. 2026-09-04 05:06 UTCEPSS rescore
  17. 2026-09-02 14:12 UTCEPSS rescore
  18. 2026-09-01 13:53 UTCEPSS rescore
  19. 2026-09-01 04:39 UTCEPSS rescore
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-30 01:22 UTCEPSS rescore
  22. 2026-08-28 21:41 UTCEPSS rescore
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:49 UTCEPSS rescore
Show 75 more
  1. 2026-08-23 16:21 UTCEG score recompute
  2. 2026-08-23 16:21 UTCVendor advisory
  3. 2026-08-23 16:21 UTCGHSA enrichment
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-21 23:49 UTCEPSS rescore
  6. 2026-08-21 21:28 UTCEG score recompute
  7. 2026-08-21 21:28 UTCVendor advisory
  8. 2026-08-21 21:28 UTCGHSA enrichment
  9. 2026-08-20 22:55 UTCEPSS rescore
  10. 2026-08-20 18:15 UTCEG score recompute
  11. 2026-08-20 18:15 UTCVendor advisory
  12. 2026-08-20 18:15 UTCGHSA enrichment
  13. 2026-08-19 17:03 UTCEPSS rescore
  14. 2026-08-18 13:48 UTCEPSS rescore
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-17 09:33 UTCVendor advisory
  17. 2026-08-17 09:33 UTCGHSA enrichment
  18. 2026-08-16 16:32 UTCEG score recompute
  19. 2026-08-16 16:32 UTCVendor advisory
  20. 2026-08-16 16:32 UTCGHSA enrichment
  21. 2026-08-16 14:56 UTCEPSS rescore
  22. 2026-08-16 03:06 UTCEG score recompute
  23. 2026-08-16 03:06 UTCVendor advisory
  24. 2026-08-16 03:06 UTCGHSA enrichment
  25. 2026-08-16 02:14 UTCEPSS rescore
  26. 2026-08-15 03:49 UTCEG score recompute
  27. 2026-08-15 03:49 UTCVendor advisory
  28. 2026-08-15 03:49 UTCGHSA enrichment
  29. 2026-08-15 01:30 UTCEPSS rescore
  30. 2026-08-14 14:46 UTCVendor advisory
  31. 2026-08-14 14:46 UTCGHSA enrichment
  32. 2026-08-14 01:43 UTCEG score recompute
  33. 2026-08-14 01:43 UTCVendor advisory
  34. 2026-08-14 01:43 UTCGHSA enrichment
  35. 2026-08-13 22:00 UTCEPSS rescore
  36. 2026-08-13 05:54 UTCVendor advisory
  37. 2026-08-13 05:54 UTCGHSA enrichment
  38. 2026-08-12 16:11 UTCEG score recompute
  39. 2026-08-12 16:11 UTCVendor advisory
  40. 2026-08-12 16:11 UTCGHSA enrichment
  41. 2026-08-12 13:51 UTCEPSS rescore
  42. 2026-08-12 03:04 UTCEG score recompute
  43. 2026-08-12 03:04 UTCVendor advisory
  44. 2026-08-12 03:04 UTCGHSA enrichment
  45. 2026-08-11 13:43 UTCEPSS rescore
  46. 2026-08-11 13:41 UTCVendor advisory
  47. 2026-08-11 13:41 UTCGHSA enrichment
  48. 2026-08-11 00:22 UTCEG score recompute
  49. 2026-08-11 00:22 UTCVendor advisory
  50. 2026-08-11 00:22 UTCGHSA enrichment
  51. 2026-08-11 00:00 UTCEPSS rescore
  52. 2026-08-10 01:44 UTCEG score recompute
  53. 2026-08-10 01:44 UTCVendor advisory
  54. 2026-08-10 01:44 UTCGHSA enrichment
  55. 2026-08-09 13:46 UTCEPSS rescore
  56. 2026-08-09 12:40 UTCVendor advisory
  57. 2026-08-09 12:40 UTCGHSA enrichment
  58. 2026-08-08 23:37 UTCEG score recompute
  59. 2026-08-08 23:37 UTCVendor advisory
  60. 2026-08-08 23:37 UTCGHSA enrichment
  61. 2026-08-08 16:37 UTCEPSS rescore
  62. 2026-08-08 02:48 UTCEG score recompute
  63. 2026-08-08 02:48 UTCVendor advisory
  64. 2026-08-08 02:48 UTCGHSA enrichment
  65. 2026-08-07 13:45 UTCVendor advisory
  66. 2026-08-07 13:45 UTCGHSA enrichment
  67. 2026-08-07 00:43 UTCEG score recompute
  68. 2026-08-07 00:43 UTCVendor advisory
  69. 2026-08-07 00:43 UTCGHSA enrichment
  70. 2026-08-06 13:46 UTCEPSS rescore
  71. 2026-08-06 10:06 UTCVendor advisory
  72. 2026-08-06 10:06 UTCGHSA enrichment
  73. 2026-08-05 21:03 UTCEG score recompute
  74. 2026-08-05 21:03 UTCVendor advisory
  75. 2026-08-05 21:03 UTCGHSA enrichment

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-40033?
CVE-2026-40033 is a high vulnerability published on May 26, 2026. FreeRDP before 3.26.0 contains a heap-buffer-overflow vulnerability in gdiCacheToSurface that allows remote attackers to write out-of-bounds heap memory. The vulnerability occurs because rectangle validation clamps coordinates to UINT16MAX but performs copy operations using unclamped cache entry…
When was CVE-2026-40033 disclosed?
CVE-2026-40033 was first published in the National Vulnerability Database on May 26, 2026, with the most recent update on July 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40033 actively exploited?
CVE-2026-40033 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 37.6% of all scored CVEs.
What is the CVSS score of CVE-2026-40033?
CVE-2026-40033 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-40033?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40033, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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