Threat Intelligence / CVE / CVE-2026-43500

CVE-2026-43500 — Linux Kernel

CVSS v3.1 7.8 (HIGH) · EPSS 26.9% (higher than 96.4% of all scored CVEs) · Priority 7.8/10 · Published 2026-05-11

As of 2026-05-20, CVE-2026-43500 is a HIGH-severity vulnerability in Linux Kernel, CVSS v3.1 7.8, EPSS 26.9% (96.4th percentile). Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-43500, most recently “Linux Kernel LPE Surge: Copy Fail (CVE-2026-31431), Dirty Frag/Fragnesia (CVE-2026-43284/CVE-2026-43500/CVE-2026-46300), and CrackArmor AppArmor Flaws vs. Defense-in-Depth Mitigations”.

Last updated: 2026-05-20

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 125 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)
26.9% probability of exploitation in the next 30 days, higher than 96.4% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
7.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-05-11, last modified 2026-05-20

Is CVE-2026-43500 being exploited?

It currently carries a trending score of 29 in the Threadlinqs vulnerability feed.

Affected products and versions

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

Seeded from cveorg and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-43500 are available via the Threadlinqs MCP server (Purple tier). View plans →

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