CVE-2026-63821

UNRATEDCVSS · not yet scoredTrending — 3 sources updated this week
—
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

wifi: rtw88: usb: fix memory leaks on USB write failures

When rtw_usb_write_port() fails to submit a USB Request Block (URB) (e.g., due to device disconnect or ENOMEM), the completion callback is never executed.

Currently, the driver ignores the return value of rtw_usb_write_port() in rtw_usb_write_data() and rtw_usb_tx_agg_skb(). Because these functions rely on the completion callback to free the socket buffers (skbs) and the transaction control block (txcb), a submission failure results in:

  • A memory leak of the allocated skb in rtw_usb_write_data().
  • A memory leak of the txcb structure and all aggregated skbs in
rtw_usb_tx_agg_skb().

Fix this by checking the return value of rtw_usb_write_port(). If it fails, explicitly free the skb in rtw_usb_write_data(), and properly purge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb().

The issue was discovered in practice during device disconnect/reconnect scenarios and memory pressure conditions. Tested by verifying normal TX operation continues after the fix without regressions.

CVSS v3
—
EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
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EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

July 19, 2026

Last Modified

August 17, 2026

References (5)

Vendor Advisories for CVE-2026-63821(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
ubuntulinux-virtual-hwe-26.04-edge (7.0.0-31.31) @ resolute2026-09-11ubuntu
ubuntulinux-tools-oem-7.0 (7.0.0-1013.13) @ resolute2026-09-11ubuntu
ubuntulinux-tools-gcp-edge (7.0.0-1011.11~24.04.1) @ noble2026-09-11ubuntu

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

(2 across 2 ecosystems)
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.95-1~bpo12+1 (29 versions)6.12.95-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (156 versions)7.1.3-1—

Additional Vendor Advisories

(3)

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 10× in last 7d / 41× 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. 2026-09-11 20:32 UTCVendor advisory
  2. 2026-09-11 20:32 UTCGHSA enrichment
  3. 2026-09-11 14:53 UTCEPSS rescore
  4. 2026-09-11 09:37 UTCEPSS rescore
  5. 2026-09-08 22:01 UTCEPSS rescore
  6. 2026-09-07 16:01 UTCEPSS rescore
  7. 2026-09-06 13:47 UTCEPSS rescore
  8. 2026-09-05 20:14 UTCVendor advisory
  9. 2026-09-05 20:14 UTCGHSA enrichment
  10. 2026-09-05 15:31 UTCEPSS rescore
  11. 2026-09-04 05:07 UTCEPSS rescore
  12. 2026-09-02 14:12 UTCEPSS rescore
  13. 2026-09-01 13:54 UTCEPSS rescore
  14. 2026-08-30 19:17 UTCEPSS rescore
  15. 2026-08-30 03:03 UTCVendor advisory
  16. 2026-08-30 03:03 UTCGHSA enrichment
  17. 2026-08-28 21:42 UTCEPSS rescore
  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 22:29 UTCVendor advisory
  20. 2026-08-26 22:29 UTCGHSA enrichment
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-23 12:44 UTCVendor advisory
  24. 2026-08-23 12:44 UTCGHSA enrichment
  25. 2026-08-23 00:19 UTCEPSS rescore
Show 75 more
  1. 2026-08-21 23:49 UTCEPSS rescore
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-20 09:04 UTCVendor advisory
  4. 2026-08-20 09:04 UTCGHSA enrichment
  5. 2026-08-19 17:04 UTCEPSS rescore
  6. 2026-08-18 13:48 UTCEPSS rescore
  7. 2026-08-17 13:47 UTCEPSS rescore
  8. 2026-08-17 05:25 UTCNVD update
  9. 2026-08-17 05:23 UTCVendor advisory
  10. 2026-08-17 05:23 UTCGHSA enrichment
  11. 2026-08-17 05:05 UTCMITRE cvelistV5
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-15 15:58 UTCVendor advisory
  14. 2026-08-15 15:58 UTCGHSA enrichment
  15. 2026-08-15 01:30 UTCEPSS rescore
  16. 2026-08-13 22:00 UTCEPSS rescore
  17. 2026-08-12 13:51 UTCEPSS rescore
  18. 2026-08-12 12:17 UTCGHSA enrichment
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-09 13:47 UTCEPSS rescore
  21. 2026-08-09 08:35 UTCGHSA enrichment
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-06 13:47 UTCEPSS rescore
  24. 2026-08-06 04:54 UTCGHSA enrichment
  25. 2026-08-05 19:17 UTCEPSS rescore
  26. 2026-08-05 19:17 UTCEPSS rescore
  27. 2026-08-04 15:10 UTCEPSS rescore
  28. 2026-08-04 10:39 UTCEPSS rescore
  29. 2026-08-03 10:36 UTCEPSS rescore
  30. 2026-08-03 01:14 UTCGHSA enrichment
  31. 2026-08-02 02:27 UTCEPSS rescore
  32. 2026-08-01 04:16 UTCEPSS rescore
  33. 2026-07-30 21:34 UTCEG score recompute
  34. 2026-07-30 21:34 UTCGHSA enrichment
  35. 2026-07-30 16:28 UTCEPSS rescore
  36. 2026-07-30 01:30 UTCEPSS rescore
  37. 2026-07-30 01:30 UTCEPSS rescore
  38. 2026-07-28 15:37 UTCEPSS rescore
  39. 2026-07-27 17:53 UTCGHSA enrichment
  40. 2026-07-27 14:14 UTCEPSS rescore
  41. 2026-07-26 14:54 UTCEPSS rescore
  42. 2026-07-26 14:54 UTCEPSS rescore
  43. 2026-07-26 11:08 UTCEG score recompute
  44. 2026-07-26 11:08 UTCGHSA enrichment
  45. 2026-07-24 14:18 UTCEPSS rescore
  46. 2026-07-24 14:18 UTCEPSS rescore
  47. 2026-07-23 14:18 UTCEPSS rescore
  48. 2026-07-23 14:18 UTCEPSS rescore
  49. 2026-07-23 03:22 UTCEG score recompute
  50. 2026-07-22 14:08 UTCEPSS rescore
  51. 2026-07-22 14:08 UTCEPSS rescore
  52. 2026-07-21 15:25 UTCEPSS rescore
  53. 2026-07-21 15:25 UTCEPSS rescore
  54. 2026-07-20 17:44 UTCEG score recompute
  55. 2026-07-20 17:44 UTCGHSA enrichment
  56. 2026-07-20 17:08 UTCEPSS rescore
  57. 2026-07-19 15:42 UTCGHSA enrichment
  58. 2026-07-19 15:39 UTCGHSA enrichment
  59. 2026-07-19 15:36 UTCGHSA enrichment
  60. 2026-07-19 15:28 UTCGHSA enrichment
  61. 2026-07-19 15:28 UTCGHSA enrichment
  62. 2026-07-19 15:26 UTCGHSA enrichment
  63. 2026-07-19 15:18 UTCGHSA enrichment
  64. 2026-07-19 15:18 UTCGHSA enrichment
  65. 2026-07-19 15:17 UTCGHSA enrichment
  66. 2026-07-19 15:16 UTCGHSA enrichment
  67. 2026-07-19 15:15 UTCGHSA enrichment
  68. 2026-07-19 15:15 UTCGHSA enrichment
  69. 2026-07-19 15:14 UTCGHSA enrichment
  70. 2026-07-19 15:13 UTCGHSA enrichment
  71. 2026-07-19 15:12 UTCGHSA enrichment
  72. 2026-07-19 15:10 UTCGHSA enrichment
  73. 2026-07-19 15:09 UTCGHSA enrichment
  74. 2026-07-19 15:07 UTCGHSA enrichment
  75. 2026-07-19 15:05 UTCGHSA enrichment

Frequently asked(4)

What is CVE-2026-63821?
CVE-2026-63821 is a publicly disclosed vulnerability published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: wifi: rtw88: usb: fix memory leaks on USB write failures When rtwusbwrite_port() fails to submit a USB Request Block (URB) (e.g., due to device disconnect or ENOMEM), the completion callback is never executed. Currently, the driver…
When was CVE-2026-63821 disclosed?
CVE-2026-63821 was first published in the National Vulnerability Database on July 19, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63821 actively exploited?
CVE-2026-63821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 93.2% of all scored CVEs.
How do I remediate CVE-2026-63821?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63821, 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.

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