How severe is CVE-2026-43284?

CVE-2026-43284 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-43284?

CVE-2026-43284 affects the following packages: Kernel (Linux). Ecosystems affected: Linux.

How do I fix CVE-2026-43284?

Update Kernel to 5.10.255 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43284 is resolved across your whole dependency graph.

How do I detect CVE-2026-43284 in my Linux dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-43284 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-43284 actively exploited in the wild?

Yes. There are 10 known exploit references for CVE-2026-43284, including 2 documented proof-of-concept exploits on Exploit-DB. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2026-43284?

CVE-2026-43284 has an EPSS (Exploit Prediction Scoring System) score of 94.2%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2026-43284?

CVE-2026-43284 is classified as CWE-123 (CWE-123). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2026-43284?

2 Metasploit modules reference CVE-2026-43284, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-43284 published, and has it been updated?

CVE-2026-43284 was published on May 8, 2026 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐧

🐧 Linux

Not in CISA KEV

HIGH severity

CVE-2026-43284 — Kernel

HIGH

CVE-2026-43284 is a high-severity (CVSS 8.8) CWE-123 vulnerability in Kernel. 10 public exploit references exist, so weaponization risk is real. A fix is available for Kernel — see the affected versions and patch details below.

xfrm: esp: avoid in-place decrypt on shared skb frags

Published

May 8, 2026

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

10 known

Exploitation data as of Oct 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43284.

EPSS Exploitation Probability

via FIRST.org ↗

94.2%probability of exploitation in next 30 days

Very High Risk+91.72%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-43284 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 396,966 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐧Kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.

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().

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐧Linux	`Kernel`	≥ 4.11.0&&< 5.10.255	5.10.255

Affected Products

1 product · 7 configurations

linux kernellinux

≥ 7.0 && < 7.0.5

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-52591locallinux

Linux Kernel - Local Privilege Escalation

by nu11secur1ty · May 29, 2026

Exploit-DB Source

EDB-52585locallinux

Linux Kernel - Local Privilege Escalation

by nu11secur1ty · May 27, 2026

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Kernel to 5.10.255 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43284 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This issue is classified as Important, rather than Critical severity, because exploitation requires local access to the system. A low-privileged local attacker can exploit this flaw in the Linux kernel's xfrm-ESP and RxRPC subsystems to gain root privileges by overwriting sensitive system files. Exploitation does not…

Workaround published by Red Hat

See the security bulletin for a detailed mitigation procedure.

Source: Red Hat security advisory for CVE-2026-43284 (CC BY 4.0)

Product	Fixed in	Advisory
NVIDIA for RHEL 10	`kernel-0:6.12.0-211.7.el10nv`	RHSA-2026:17795
NVIDIA for RHEL 10	`kernel-0:6.12.0-231.12.el10nv`	RHSA-2026:33486
Red Hat Enterprise Linux 10	`kernel-0:6.12.0-124.56.1.el10_1`	RHSA-2026:16062
Red Hat Enterprise Linux 10	`kernel-0:6.12.0-211.7.3.el10_2`	RHSA-2026:19074
Red Hat Enterprise Linux 10	`kernel-0:6.12.0-211.16.1.el10_2`	RHSA-2026:19569
Red Hat Enterprise Linux 10.0 Extended Update Support	`kernel-0:6.12.0-55.73.1.el10_0`	RHSA-2026:16314
Red Hat Enterprise Linux 8	`kernel-rt-0:4.18.0-553.124.1.rt7.465.el8_10`	RHSA-2026:16196
Red Hat Enterprise Linux 8	`kernel-0:4.18.0-553.124.1.el8_10`	RHSA-2026:16195

UbuntuHIGH

USN-8370-1Ubuntu USN-8371-1Ubuntu USN-8373-1Ubuntu USN-8374-1Ubuntu USN-8388-1Ubuntu USN-8389-1Ubuntu USN-8390-1Ubuntu USN-8391-1Ubuntu

Frequently Asked Questions

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

O3 Security · Impact-Aware SCA

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