[HIGH] CVE-2026-43284 — CVSS 7.8 (May 8, 2026)

A HIGH-severity vulnerability identified as CVE-2026-43284 has been published on May 8, 2026 with a CVSS base score of 7.8. The vulnerability affects Linux Linux kernel. This security advisory provides a detailed breakdown of the vulnerability, its potential impact, weakness classification, and actionable steps to protect your systems.

Vulnerability Details

CVE ID: CVE-2026-43284
Severity: HIGH
CVSS Score: 7.8
Published: May 8, 2026
Affected Product: Linux Linux kernel
Weakness (CWE): CWE-123

Technical Description

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().

Potential Impact

If exploited, this high-severity vulnerability could allow an attacker to compromise sensitive data confidentiality, tamper with system integrity, cause a denial of service. Organizations running Linux Linux kernel should treat this as a priority remediation item.

Recommended Action

A patch or vendor advisory is available. Take the following steps immediately:

1. Review the vendor advisory linked in the References section below.
2. Identify all instances of the affected software in your environment.
3. Apply the available patch or upgrade to the fixed version as soon as possible.
4. If patching is not immediately possible, implement compensating controls such as WAF rules, network segmentation, or disabling the affected feature.
5. Monitor your systems for signs of exploitation using your SIEM or IDS/IPS.

View full details on NVD →

References

• Patch
• Patch
• Patch
• Patch
• Reference 5

Related Security Advisories

• [HIGH] CVE-2025-9661 — CVSS 8.1 (May 7, 2026) — HIGH / CVSS 8.1
• [HIGH] CVE-2026-23928 — CVSS 7.3 (May 6, 2026) — HIGH / CVSS 7.3
• [HIGH] CVE-2026-23926 — CVSS 7.3 (May 6, 2026) — HIGH / CVSS 7.3