CVE-2026-67303

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

Score 4.3 from GitHub Security Advisory published 2026-08-01. A secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 4.3Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in channels/serial/client/serial_main.c. When serial device redirection is enabled and a server-controlled IRP_MJ_DEVICE_CONTROL request specifies an unsupported IOCTL with a non-zero OutputBufferLength, CommDeviceIoControl() can fail with BytesReturned = 0, causing the mismatch to trigger the assertion and abort the client process (denial of service).

CVSS v3
4.3
EG Score
4.3MEDIUMmedium confidence
EG Risk
35
EG Risk 35/100CISA SSVC

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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
33rd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 1, 2026

Last Modified

September 29, 2026

Advisory Details (4)

Auto-updated Aug 1, 2026
Patch available. Sources: github, github_commit.
generic

FreeRDP before 3.29.0 Denial of Service via serial DeviceControl | Advisories | VulnCheck

https://www.vulncheck.com/advisories/freerdp-before-denial-of-service-via-serial-devicecontrol
github_commit

commit 5370fb26fbf0 (FreeRDP/FreeRDP)

Fix landed in FreeRDP/FreeRDP commit 5370fb26fbf0 — awaiting tagged release

https://github.com/FreeRDP/FreeRDP/commit/5370fb26fbf034ecd11d3026b6ad639b5fff493f
github_commit

commit 1cc783d4c78b (FreeRDP/FreeRDP)

Fix landed in FreeRDP/FreeRDP commit 1cc783d4c78b — awaiting tagged release

https://github.com/FreeRDP/FreeRDP/commit/1cc783d4c78bd2f66d3a8582dfe70a663d141444
github Patch Available

FreeRDP serial DeviceControl reachable assertion DoS · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pfxq-3qmw-8vjx

Vendor Advisories for CVE-2026-67303(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp22.10.0+dfsg1-1 ... 2.9.0+dfsg1-1~bpo11+1 (32 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp22.10.0+dfsg1-1 ... 2.11.7+dfsg1-6~deb12u1 (13 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp33.15.0+dfsg-2.1 ... 3.32.1+dfsg-1~bpo13+1 (49 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp33.15.0+dfsg-2.1 ... 3.28.0+dfsg-2 (37 versions)
  • every version up to 3.29.0+dfsg-1: fixed in 3.29.0+dfsg-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 65× 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 164 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-67303?
CVE-2026-67303 is a medium vulnerability published on August 1, 2026. FreeRDP before 3.29.0 contains a reachable assertion (WINPRASSERT(OutputBufferLength == BytesReturned)) in serialprocessirpdevicecontrol() in channels/serial/client/serialmain.c. When serial device redirection is enabled and a server-controlled IRPMJDEVICE_CONTROL request specifies an unsupported…
When was CVE-2026-67303 disclosed?
CVE-2026-67303 was first published on August 1, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-67303 actively exploited?
CVE-2026-67303 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-67303?
CVE-2026-67303 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-67303?
A fix for CVE-2026-67303 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-67303 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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