7.8

CVE-2026-81000: linux

CVSS: 7.8v3.1HighReceived
AliasesUBUNTU-CVE-2026-81000DEBIAN-CVE-2026-81000
Published 11-09-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-81000 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 27.9% of scored vulnerabilities.

Overall risk
31/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.36%
0%100%
Low · +0.19 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 25 · Related 10
OPENSUSE-SU-2026:11805-1OPENSUSE-SU-2026:22091-1RHSA-2026:71016RHSA-2026:71213RHSA-2026:71232RHSA-2026:71233

Timeline

  1. 11-09-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.36%

Chance of exploitation in the next 30 days

Percentile

28%

Versus all other CVEs

30-day change

+0.19 pp

From 0.16% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.36%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu168 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linuxAll versions (No fix recorded) | < 6.1.190-1 | < 6.12.111-1 | < 7.2.6-1
  • linux-6.12< 6.12.111-1~deb12u1
Linux1 product
  • linux≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < ad715e713610d2d5473c3a6498c825ccecf26491 | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < 708e87937de93f445225c134a2e20519f9b4ce60 | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < 18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76 | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < 010eee265d6bd8769b6a523d2a0693d9b3f5df43 | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < 379d85c7f25f3e05a428225e6b8a65613c6e9b9d | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < e098d9cc8859614a7f7baebc96e32a5a16b18ed2 | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < 0ada54ea63e48b9c1608e917ccb7dfadbe86db28 | ≥ eaea34b23c46bf17b4a5638be69ab3561854f34b, < 447c9303942c439a117d9b76ce6d6e2116b38ee7 | 4.6

3 vendors · 171 products

References

13 links
Show all 13 references