CVE-2026-81000

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-11. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — Patch released this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

net: tun: bound receive headroom

tun_get_user() uses tun->align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP.

When align is larger than the usable space in a one-page skb head, SKB_MAX_HEAD(align) underflows and the result becomes negative when stored in good_linear. That value later wraps when assigned to the size_t linear variable, and tun_alloc_skb() can place skb->data outside the allocated head.

Bound the headroom stored by TUN to the one-page skb-head budget and the largest non-sentinel 16-bit skb header offset. Leave one linear byte for raw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN.

Also pull the raw-TUN protocol byte and the TAP Ethernet header before accessing them, so these checks remain safe for nonlinear skbs supplied by other allocation paths.

CVSS v3
7.8
EG Score
7.8HIGHhigh confidence
EG Risk
40
EG Risk 40/100CISA 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
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
27th
KEV
Not listed

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

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). 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

September 11, 2026

Last Modified

September 14, 2026

Advisory Details (4)

Auto-updated Sep 13, 2026
Patch available.
generic

net: tun: bound receive headroom - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/447c9303942c439a117d9b76ce6d6e2116b38ee7
generic

net: tun: bound receive headroom - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0ada54ea63e48b9c1608e917ccb7dfadbe86db28
generic

net: tun: bound receive headroom - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e098d9cc8859614a7f7baebc96e32a5a16b18ed2
generic

net: tun: bound receive headroom - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/379d85c7f25f3e05a428225e6b8a65613c6e9b9d

Vendor Advisories for CVE-2026-81000(15)

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

Patch Availability(15)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatkernel-0:6.12.0-259.27.el10nv2026-09-30redhat
redhatkernel-0:6.12.0-211.59.1.el10_22026-09-24redhat
redhatkernel-0:4.18.0-553.167.1.el8_102026-09-24redhat
redhatkernel-0:4.18.0-305.209.1.el8_42026-09-24redhat
redhatkernel-0:4.18.0-477.170.1.el8_82026-09-24redhat
redhatkernel-0:5.14.0-284.194.1.el9_22026-09-24redhat
redhatkernel-0:5.14.0-570.144.1.el9_62026-09-24redhat
redhatkernel-0:5.14.0-687.51.1.el9_82026-09-24redhat
redhatkernel-rt-0:3.10.0-1160.164.1.rt56.1316.el72026-09-24redhat
redhatkernel-0:3.10.0-1160.164.1.el72026-09-24redhat
redhatkernel-0:4.18.0-372.218.1.el8_62026-09-24redhat
redhatkernel-rt-0:5.14.0-284.194.1.rt14.479.el9_22026-09-24redhat
redhatkernel-0:5.14.0-427.152.1.el9_42026-09-24redhat
redhatkernel-0:6.12.0-55.107.1.el10_02026-09-24redhat
redhatkernel-rt-0:4.18.0-553.167.1.rt7.508.el8_102026-09-23redhat

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 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (360 versions)
  • every version on: no fix on record
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1, 6.12.107-1~deb12u1
  • every version up to 6.12.111-1~deb12u1: fixed in 6.12.111-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (35 versions)
  • every version up to 6.12.111-1: fixed in 6.12.111-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (179 versions)
  • every version up to 7.2.6-1: fixed in 7.2.6-1
—

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 40× in last 7d / 119× 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 119 total refreshes for this CVE.

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

Related CVEs(same vendor)

Frequently asked(5)

What is CVE-2026-81000?
CVE-2026-81000 is a high vulnerability published on September 11, 2026. In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser() uses tun->align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align…
When was CVE-2026-81000 disclosed?
CVE-2026-81000 was first published on September 11, 2026, with the most recent update on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81000 actively exploited?
CVE-2026-81000 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (27th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-81000?
CVE-2026-81000 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-81000?
A fix for CVE-2026-81000 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-81000 are linked in the Vendor Advisories panel on this page.

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