CVE-2026-43500 — Linux Kernel Vulnerability

What is CVE-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 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.

The record classifies CVE-2026-43500 under weakness class CWE-787. Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 158 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 7.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST): 2.2% probability of exploitation in the next 30 days, higher than 82.4% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 9.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-05-11, last modified 2026-09-01

Is CVE-2026-43500 being exploited?

Weaponised exploit code for CVE-2026-43500 is publicly available. 3 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.

attaattaatta/CVE-2026-43500 (github)
vorkampfer/dirty_frag_mitigation (github)
trickest/cve (trickest)

Affected products and versions

Linux: Kernel

How to fix CVE-2026-43500

The record marks a vendor fix as available for CVE-2026-43500. Patch reference: https://git.kernel.org/stable/c/d45179f8795222ce858770dc619abe51f9d24411. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-43500

2 tracked threats in the Threadlinqs corpus reference CVE-2026-43500, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Enriched from CVE.org, NVD, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10. This product uses the NVD API but is not endorsed or certified by the NVD.

CVE-2026-43500 — Linux Kernel