ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-43284

Linux Kernel Write-what-where Condition

Published May 8, 2026 · catalog updated Sep 8, 2026 · Linux Kernel

Patch now

CVE-2026-43284 is in the CISA known-exploited catalog. Confirm Linux Kernel against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
High8.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
94.19%
Remediation
Remediation guidance
Affected products
cpe linux/linux kernel · vendor Linux Kernel

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().

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe linux/linux kernelversion unspecified
  • vendor Linux Kernelversion unspecified

How to fix CVE-2026-43284

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-43284 is in the CISA known-exploited catalog. Confirm Linux Kernel against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-123. EPSS 94.19%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Technology hubs

Fortinet security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 8, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  2. May 8, 2026 · NIST NVD

    Detected

    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 sp

  3. Sep 8, 2026 · NIST NVD

    Updated

    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 sp

Sources

  • CVE.orgVulnerability recordCVE-2026-43284

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-43284

    30-day exploitation probability 94.2%

    first.org
  • Fortinet PSIRTVendor advisoryCVE-2026-43284

    CVSSv3 Score: 8.8 Linux kernel is impacted by CVE-2026-43284 and CVE-2026-43500 which chained together create the Dirty Frag vulnerability.CVE-2026-43284In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_S

    fortiguard.fortinet.com
  • Metasploit ModulesPublic exploit moduleexploit_linux/local/cve_2026_43284_dirty_frag

    Public module reference (good). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-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 th

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.