Threat Intelligence / CVE / CVE-2026-43284

CVE-2026-43284 — Linux Kernel

CVSS v3.1 8.8 (HIGH) · EPSS 25.5% (higher than 96.3% of all scored CVEs) · Priority 8.3/10 · Published 2026-05-08

As of 2026-05-26, CVE-2026-43284 is a HIGH-severity vulnerability in Linux Kernel, CVSS v3.1 8.8, EPSS 25.5% (96.3th percentile). Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-43284, most recently “Linux Kernel LPE Surge: Copy Fail (CVE-2026-31431), Dirty Frag/Fragnesia (CVE-2026-43284/CVE-2026-43500/CVE-2026-46300), and CrackArmor AppArmor Flaws vs. Defense-in-Depth Mitigations”.

Last updated: 2026-05-26

What is CVE-2026-43284?

In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().

The record classifies CVE-2026-43284 under weakness class CWE-123. Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 128 days ago.

Severity and exploitation probability

CVSS v3.1 base score
8.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS (FIRST)
25.5% probability of exploitation in the next 30 days, higher than 96.3% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
8.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-05-08, last modified 2026-05-26

Is CVE-2026-43284 being exploited?

It currently carries a trending score of 29 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-43284

The record marks a vendor fix as available for CVE-2026-43284. Patch reference: https://git.kernel.org/stable/c/b54edf1e9a3fd3491bdcb82a21f8d21315271e0d. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-43284

2 tracked threats in the Threadlinqs corpus reference CVE-2026-43284, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Seeded from cveorg and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-43284 are available via the Threadlinqs MCP server (Purple tier). View plans →

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