CVE-2026-63993

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-19. the CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
Trending — 4 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

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

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()

skb_tunnel_check_pmtu() can change skb->head.

Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF.

Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c.

Found by Sashiko.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity98% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
43%
KEV
Not listed

Published

July 19, 2026

Last Modified

August 5, 2026

Advisory Details (8)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a
generic

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0

Vendor Advisories for CVE-2026-63993(2)

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

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-oracle-7.0 (7.0.0-1008.8) @ resolute2026-09-18ubuntu
ubuntulinux-tools-azure-fde-7.0 (7.0.0-1009.9) @ resolute2026-09-18ubuntu
ubuntulinux-tools-raspi-realtime-7.0 (7.0.0-1015.15) @ resolute2026-09-18ubuntu
ubuntulinux-tools-nvidia-hwe-24.04-edge (7.0.0-1016.16) @ resolute2026-09-18ubuntu
ubuntulinux-tools-nvidia-hwe-26.04 (7.0.0-2016.16) @ resolute2026-09-18ubuntu
ubuntulinux-tools-gcp-edge (7.0.0-1011.11~24.04.1) @ noble2026-09-18ubuntu
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1035.38) @ noble2026-09-18ubuntu
redhatkernel-0:6.12.0-211.52.1.el10_22026-09-08redhat

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
linux5.10.103-1 ... 5.10.92-2 (54 versions)5.10.259-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)6.1.176-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.94-1~bpo12+1 (27 versions)6.12.94-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (141 versions)7.0.12-1—

Additional Vendor Advisories

(7)

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 42× in last 7d / 199× 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 557 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-63993?
CVE-2026-63993 is a critical vulnerability published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: vxlan: do not reuse cached iphdr() value after skbtunnelcheckpmtu() skbtunnelcheck_pmtu() can change skb->head. Reusing oldiph afer skbtunnelcheckpmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and…
When was CVE-2026-63993 disclosed?
CVE-2026-63993 was first published in the National Vulnerability Database on July 19, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63993 actively exploited?
CVE-2026-63993 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 57.2% of all scored CVEs.
What is the CVSS score of CVE-2026-63993?
CVE-2026-63993 has a CVSS v4.0 base score of 9.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-63993?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63993, 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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