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Public proof of conceptFix available

CVE-2026-43284

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

A public proof of concept exists; no exploitation attested.

  • Published2026-05-08
  • Fixed in7.0.5 · 6.18.28 · 6.12.87 · 6.6.138 · 6.1.171 · 5.15.205
  • WeaknessCWE-123

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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().

Timeline

dates in UTC
  1. 2026-05-0808:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-43284?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-43284?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Linux linux kernel
BranchAffectedFixed in
7.0≥ 7.0, < 7.0.57.0.5
6.x≥ 6.13, < 6.18.286.18.28
6.x≥ 6.7, < 6.12.876.12.87
6.x≥ 6.2, < 6.6.1386.6.138
6.1≥ 5.16, < 6.1.1716.1.171
5.x≥ 5.12, < 5.15.2055.15.205
5.10≥ 4.11, < 5.10.2555.10.255

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • kernelAlmaLinux:10all versions · fixed in 6.12.0-211.16.1.el10_2and 74 other packages
  • kernelAlmaLinux:9all versions · fixed in 5.14.0-611.54.3.el9_7and 116 other packages
  • kernelAlmaLinux:8all versions · fixed in 4.18.0-553.123.2.el8_10and 29 other packages
  • kernel-64k-uki-virtAlmaLinux:10all versions · fixed in 6.12.0-124.55.3.el10_1and 28 other packages
  • kernel-rtAlmaLinux:8all versions · fixed in 4.18.0-553.123.2.rt7.464.el8_10and 14 other packages

Vendor advisories

  • CVE-2026-43284 Red Hat Product Security3,875 products fixed

    kernel: "Dirty Frag" ESP XFRM variant is a new universal Local Privilege Escalation (LPE) vulnerability in the Linux kernel

  • ICSA-26-225-04 CISA1 known affected

    Hitachi Energy APM Edge Product

    APM Edge versions 6.10 and prior

  • ICSA-26-209-04 CISA5 known affected

    Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.6 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.6 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.6 · +2 more

  • SSA-019113 Siemens ProductCERT5 known affected

    SSA-019113: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.6

    SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= V3.1.6 < V3.1.7 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.6 < V3.1.7 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.6 < V3.1.7 · +2 more

  • RHSA-2026:34098 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.17.55 bug fix and security update

  • RHSA-2026:33486 Red Hat Product Security47 products fixed

    Red Hat Security Advisory: kernel security, bug fix, and enhancement update

38 more advisories

Full record on NVD

Fix

  1. Update Linux linux kernel to 7.0.5 · 6.18.28 · 6.12.87 · 6.6.138 · 6.1.171 · 5.15.205 · 5.10.255
  2. Vendor fix Siemens ProductCERT SSA-019113 · 5 productsUpdate to V3.1.7 or later version
  3. Vendor fix Red Hat Product Security RHSA-2026:34098 · 4 productsFor OpenShift Container Platform 4.17 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
  4. Vendor fix Red Hat Product Security RHSA-2026:33486 · 47 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect.
  5. Vendor fix Red Hat Product Security RHSA-2026:26542 · 1 productFor OpenShift Container Platform 4.13 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
  6. Vendor fix Red Hat Product Security RHSA-2026:23233 · 4 productsFor OpenShift Container Platform 4.15 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
  7. Vendor fix CISA ICSA-26-174-06 · 1 productFor affected products, software updates should be installed upon availability. Product Patch version - APROL : APROL-AutoYaST-DVD- V4.4-010.10.260602 Until remediated software versions are available, customers are required to conduct a risk assessment of their affected s…

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-52585EDB-52591
Exploit-DB
Proof-of-concept repositories
20 repositories, unverifiedPercivalll/Dirty-Frag-Kubernetes-PoCscriptzteam/Paranoid-Dirty-Frag-CVE-2026-43284mym0us3r/DIRTY-FRAG-Detection-with-Wazuh-4.14.40xBlackash/CVE-2026-43284suominen/CVE-2026-43284
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Published
2026-05-08
Last Modified
2026-09-08
NVD status
Modified
MSRC Title
xfrm: esp: avoid in-place decrypt on shared skb frags

Frequently asked questions

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().

Is CVE-2026-43284 actively exploited?

A proof-of-concept exploit exists for CVE-2026-43284, but active exploitation has not been confirmed at this time.

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

CVE-2026-43284 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

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