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

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
—
EG Score
0.0(none)
EG Risk
0
EG Risk 0/100

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. It is distinct from the 0–10 EG Score, which measures severity.

EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

July 19, 2026

Last Modified

July 19, 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.

Data Freshness Timeline

(refreshed 17× in last 7d / 74× 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.

  1. 2026-07-27 14:14 UTCEPSS rescore
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-26 14:54 UTCEPSS rescore
  4. 2026-07-26 11:08 UTCEG score recompute
  5. 2026-07-26 11:08 UTCGHSA enrichment
  6. 2026-07-24 14:18 UTCEPSS rescore
  7. 2026-07-24 14:18 UTCEPSS rescore
  8. 2026-07-23 14:18 UTCEPSS rescore
  9. 2026-07-23 14:18 UTCEPSS rescore
  10. 2026-07-23 03:22 UTCEG score recompute
  11. 2026-07-22 14:08 UTCEPSS rescore
  12. 2026-07-22 14:08 UTCEPSS rescore
  13. 2026-07-21 15:25 UTCEPSS rescore
  14. 2026-07-21 15:25 UTCEPSS rescore
  15. 2026-07-20 17:44 UTCEG score recompute
  16. 2026-07-20 17:44 UTCGHSA enrichment
  17. 2026-07-20 17:08 UTCEPSS rescore
  18. 2026-07-19 15:42 UTCGHSA enrichment
  19. 2026-07-19 15:39 UTCGHSA enrichment
  20. 2026-07-19 15:36 UTCGHSA enrichment
  21. 2026-07-19 15:28 UTCGHSA enrichment
  22. 2026-07-19 15:28 UTCGHSA enrichment
  23. 2026-07-19 15:26 UTCGHSA enrichment
  24. 2026-07-19 15:18 UTCGHSA enrichment
  25. 2026-07-19 15:18 UTCGHSA enrichment
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  1. 2026-07-19 15:17 UTCGHSA enrichment
  2. 2026-07-19 15:16 UTCGHSA enrichment
  3. 2026-07-19 15:15 UTCGHSA enrichment
  4. 2026-07-19 15:15 UTCGHSA enrichment
  5. 2026-07-19 15:14 UTCGHSA enrichment
  6. 2026-07-19 15:13 UTCGHSA enrichment
  7. 2026-07-19 15:12 UTCGHSA enrichment
  8. 2026-07-19 15:10 UTCGHSA enrichment
  9. 2026-07-19 15:09 UTCGHSA enrichment
  10. 2026-07-19 15:07 UTCGHSA enrichment
  11. 2026-07-19 15:05 UTCGHSA enrichment
  12. 2026-07-19 15:04 UTCGHSA enrichment
  13. 2026-07-19 14:59 UTCGHSA enrichment
  14. 2026-07-19 14:53 UTCGHSA enrichment
  15. 2026-07-19 14:52 UTCGHSA enrichment
  16. 2026-07-19 14:50 UTCGHSA enrichment
  17. 2026-07-19 14:38 UTCGHSA enrichment
  18. 2026-07-19 14:37 UTCGHSA enrichment
  19. 2026-07-19 14:32 UTCGHSA enrichment
  20. 2026-07-19 14:27 UTCGHSA enrichment
  21. 2026-07-19 14:25 UTCGHSA enrichment
  22. 2026-07-19 14:25 UTCGHSA enrichment
  23. 2026-07-19 14:21 UTCGHSA enrichment
  24. 2026-07-19 14:17 UTCGHSA enrichment
  25. 2026-07-19 14:16 UTCGHSA enrichment
  26. 2026-07-19 14:15 UTCGHSA enrichment
  27. 2026-07-19 14:13 UTCGHSA enrichment
  28. 2026-07-19 14:08 UTCGHSA enrichment
  29. 2026-07-19 14:07 UTCGHSA enrichment
  30. 2026-07-19 13:59 UTCGHSA enrichment
  31. 2026-07-19 13:53 UTCGHSA enrichment
  32. 2026-07-19 13:50 UTCGHSA enrichment
  33. 2026-07-19 13:49 UTCGHSA enrichment
  34. 2026-07-19 13:47 UTCGHSA enrichment
  35. 2026-07-19 13:46 UTCGHSA enrichment
  36. 2026-07-19 13:21 UTCGHSA enrichment
  37. 2026-07-19 13:18 UTCGHSA enrichment
  38. 2026-07-19 13:17 UTCGHSA enrichment
  39. 2026-07-19 13:13 UTCGHSA enrichment
  40. 2026-07-19 13:07 UTCGHSA enrichment
  41. 2026-07-19 13:06 UTCGHSA enrichment
  42. 2026-07-19 13:00 UTCGHSA enrichment
  43. 2026-07-19 12:57 UTCGHSA enrichment
  44. 2026-07-19 12:49 UTCGHSA enrichment
  45. 2026-07-19 12:46 UTCGHSA enrichment
  46. 2026-07-19 12:33 UTCGHSA enrichment
  47. 2026-07-19 12:26 UTCNVD update
  48. 2026-07-19 12:13 UTCEG score recompute
  49. 2026-07-19 12:10 UTCMITRE cvelistV5first tracked

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. 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 94.7% 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.

Dependency Blast Radius

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