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
Trending — 4 sources updated this weekElevated
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
57%
KEV
Not listed

Published

May 26, 2026

Last Modified

July 24, 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(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuwinpr3-utils (3.30.0+dfsg-0ubuntu0.24.04.1) @ noble2026-07-26ubuntu
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.

Weakness Classification(2)

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

Additional Vendor Advisories

(1)

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 15× in last 7d / 51× 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 138 total refreshes for this CVE.

  1. 2026-07-26 14:54 UTCEPSS rescore
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-26 07:48 UTCEG score recompute
  4. 2026-07-26 07:48 UTCVendor advisory
  5. 2026-07-26 07:48 UTCGHSA enrichment
  6. 2026-07-25 14:18 UTCEPSS rescore
  7. 2026-07-25 14:18 UTCEPSS rescore
  8. 2026-07-24 14:17 UTCEPSS rescore
  9. 2026-07-24 14:17 UTCEPSS rescore
  10. 2026-07-23 14:18 UTCEPSS rescore
  11. 2026-07-23 14:18 UTCEPSS rescore
  12. 2026-07-23 03:10 UTCEG score recompute
  13. 2026-07-22 14:08 UTCEPSS rescore
  14. 2026-07-21 15:24 UTCEPSS rescore
  15. 2026-07-20 17:08 UTCEPSS rescore
  16. 2026-07-19 07:52 UTCOSV refresh
  17. 2026-07-19 02:29 UTCEPSS rescore
  18. 2026-07-18 10:04 UTCEPSS rescore
  19. 2026-07-16 17:03 UTCEPSS rescore
  20. 2026-07-16 12:29 UTCNVD updateCVSS v4 → 8.7
  21. 2026-07-16 12:08 UTCMITRE cvelistV5CVSS v4 → 8.6
  22. 2026-07-15 16:57 UTCEPSS rescore
  23. 2026-07-15 16:57 UTCEPSS rescore
  24. 2026-07-15 02:25 UTCNVD updateCVSS v4 → 8.7
  25. 2026-07-15 02:00 UTCEPSS rescore
Show 75 more
  1. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v4 → 8.6
  2. 2026-07-13 22:30 UTCEPSS rescore
  3. 2026-07-12 05:46 UTCEPSS rescore
  4. 2026-07-11 08:27 UTCEPSS rescore
  5. 2026-07-09 19:10 UTCEPSS rescore
  6. 2026-07-08 15:15 UTCEPSS rescore
  7. 2026-07-08 14:36 UTCNVD updateCVSS v4 → 8.7
  8. 2026-07-08 12:47 UTCMITRE cvelistV5CVSS v4 → 8.6
  9. 2026-07-07 13:46 UTCEPSS rescore
  10. 2026-07-06 16:27 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 02:23 UTCEPSS rescore
  13. 2026-07-06 02:23 UTCEPSS rescore
  14. 2026-07-05 02:30 UTCEPSS rescore
  15. 2026-07-04 06:31 UTCEPSS rescore
  16. 2026-07-01 15:06 UTCEPSS rescore
  17. 2026-07-01 14:09 UTCGHSA enrichment
  18. 2026-06-30 23:22 UTCEPSS rescore
  19. 2026-06-30 04:33 UTCNVD updateCVSS v4 → 8.7
  20. 2026-06-29 14:59 UTCGHSA enrichment
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-28 23:43 UTCGHSA enrichment
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 09:15 UTCGHSA enrichment
  25. 2026-06-28 04:56 UTCEPSS rescore
  26. 2026-06-27 20:10 UTCGHSA enrichment
  27. 2026-06-27 07:07 UTCGHSA enrichment
  28. 2026-06-27 03:08 UTCEPSS rescore
  29. 2026-06-26 17:56 UTCGHSA enrichment
  30. 2026-06-26 02:52 UTCGHSA enrichment
  31. 2026-06-25 13:49 UTCEPSS rescore
  32. 2026-06-25 13:49 UTCEPSS rescore
  33. 2026-06-25 12:04 UTCGHSA enrichment
  34. 2026-06-24 14:05 UTCEPSS rescore
  35. 2026-06-23 21:33 UTCEPSS rescore
  36. 2026-06-22 14:25 UTCEPSS rescore
  37. 2026-06-22 14:25 UTCEPSS rescore
  38. 2026-06-21 14:56 UTCEPSS rescore
  39. 2026-06-21 14:56 UTCEPSS rescore
  40. 2026-06-21 01:59 UTCEPSS rescore
  41. 2026-06-19 19:25 UTCEPSS rescore
  42. 2026-06-18 17:52 UTCEPSS rescore
  43. 2026-06-18 17:52 UTCEPSS rescore
  44. 2026-06-17 19:25 UTCGHSA enrichment
  45. 2026-06-17 17:53 UTCEPSS rescore
  46. 2026-06-17 06:22 UTCGHSA enrichment
  47. 2026-06-16 17:52 UTCEPSS rescore
  48. 2026-06-16 17:19 UTCGHSA enrichment
  49. 2026-06-16 02:54 UTCGHSA enrichment
  50. 2026-06-15 17:49 UTCEPSS rescore
  51. 2026-06-15 13:51 UTCGHSA enrichment
  52. 2026-06-14 23:24 UTCGHSA enrichment
  53. 2026-06-14 10:21 UTCGHSA enrichment
  54. 2026-06-13 23:00 UTCEPSS rescore
  55. 2026-06-13 21:18 UTCGHSA enrichment
  56. 2026-06-13 03:28 UTCGHSA enrichment
  57. 2026-06-12 23:12 UTCEPSS rescore
  58. 2026-06-12 23:12 UTCEPSS rescore
  59. 2026-06-12 14:25 UTCGHSA enrichment
  60. 2026-06-12 01:23 UTCGHSA enrichment
  61. 2026-06-11 14:00 UTCEPSS rescore
  62. 2026-06-11 12:20 UTCGHSA enrichment
  63. 2026-06-10 23:17 UTCGHSA enrichment
  64. 2026-06-10 22:18 UTCEPSS rescore
  65. 2026-06-10 13:22 UTCEPSS rescore
  66. 2026-06-10 13:22 UTCEPSS rescore
  67. 2026-06-10 10:15 UTCGHSA enrichment
  68. 2026-06-09 21:12 UTCGHSA enrichment
  69. 2026-06-09 08:09 UTCGHSA enrichment
  70. 2026-06-08 19:06 UTCGHSA enrichment
  71. 2026-06-08 14:17 UTCEPSS rescore
  72. 2026-06-08 14:17 UTCEPSS rescore
  73. 2026-06-08 03:46 UTCGHSA enrichment
  74. 2026-06-07 15:25 UTCEPSS rescore
  75. 2026-06-07 15:25 UTCEPSS rescore

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 24, 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 42.7% 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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