Vulnerability · CVE-2026-43500

Linux Kernel Out-of-bounds Write

Published May 11, 2026 · corrected/updated Aug 24, 2026 · Linux Kernel · evidence confidence very high

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owned paged fragments (e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via __ip_append_data, or a chained skb_has_frag_list()) falls through to the in-place decryption path, which binds the frag pages directly into the AEAD/skcipher SGL via skb_to_sgvec(). Extend the gate to also unshare when skb_has_frag_list() or skb_has_shared_frag() is true. This catches the splice-loopback vector and other externally-shared frag sources while preserving the zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC page_pool RX, GRO). The OOM/trace handling already in place is reused.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-43500 is a high public vulnerability record for Linux Kernel. CISA lists it as known exploited. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether Linux Kernel is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: linux/linux kernel; linux/linux kernel (5.3); linux/linux kernel (7.1); Linux Kernel. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.8, EPSS 2.3%. CISA lists it as known exploited. Weakness classes: CWE-123, CWE-787. Sources contributing to this record: cve_org, epss, fortinet, metasploit. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

Exploitation evidence
Confirmed in CISA KEV since May 11, 2026. Listed in CISA KEV and VulnCheck KEV.
Patch and remediation
Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Technology hubs

Fortinet

Code

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

Timeline

Detection, updates, and resolution for this record.

May 11, 2026 · CISA KEV
Known exploited
Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
May 11, 2026 · NIST NVD
Detected
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owne
Aug 24, 2026 · NIST NVD
Updated
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owne

Affected

cpe linux/linux kernelversion unspecified
cpe linux/linux kernel5.3
cpe linux/linux kernel7.1
vendor Linux Kernelversion unspecified

Sources

CVE.orgVulnerability recordCVE-2026-43500
Official CVE identifier
cve.org
FIRST EPSSExploitation probabilityCVE-2026-43500
30-day exploitation probability 2.3%
first.org
Fortinet PSIRTVendor advisoryCVE-2026-43500
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_43500_dirty_frag
Public module reference (good). Module source is not copied into this catalog.
rapid7.com
NIST NVDVulnerability recordCVE-2026-43500
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before
nvd.nist.gov
VulnCheck KEVConfirmed exploitationCVE-2026-43500
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before c
vulncheck.com