Threat Intelligence / CVE / CVE-2026-31635

CVE-2026-31635 — Linux Kernel

CVSS v3.1 7.5 (HIGH) · EPSS 0.0% (higher than 11.7% of all scored CVEs) · Priority 4.2/10 · Published 2026-04-24

As of 2026-05-19, CVE-2026-31635 is a HIGH-severity vulnerability in Linux Kernel, CVSS v3.1 7.5, EPSS 0.0% (11.7th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-31635, most recently “DirtyDecrypt / DirtyCBC — Linux Kernel rxgk Root LPE with Public PoC (CVE-2026-31635)”.

Last updated: 2026-05-19

What is CVE-2026-31635?

In the Linux kernel, the following vulnerability has been resolved: rxrpc: fix oversized RESPONSE authenticator length check rxgk_verify_response() decodes auth_len from the packet and is supposed to verify that it fits in the remaining bytes. The existing check is inverted, so oversized RESPONSE authenticators are accepted and passed to rxgk_decrypt_skb(), which can later reach skb_to_sgvec() with an impossible length and hit BUG_ON(len). Decoded from the original latest-net reproduction logs with scripts/decode_stacktrace.sh: RIP: __skb_to_sgvec() [net/core/skbuff.c:5285 (discriminator 1)] Call Trace: skb_to_sgvec() [net/core/skbuff.c:5305] rxgk_decrypt_skb() [net/rxrpc/rxgk_common.h:81] rxgk_verify_response() [net/rxrpc/rxgk.c:1268] rxrpc_process_connection() [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364 net/rxrpc/conn_event.c:386] process_one_work() [kernel/workqueue.c:3281] worker_thread() [kernel/workqueue.c:3353 kernel/workqueue.c:3440] kthread() [kernel/kthread.c:436] ret_from_fork() [arch/x86/kernel/process.c:164] Reject authenticator lengths that exceed the remaining packet payload.

The record classifies CVE-2026-31635 under weakness class CWE-130. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 141 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (FIRST): 0.0% probability of exploitation in the next 30 days, higher than 11.7% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 4.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-04-24, last modified 2026-05-19

Is CVE-2026-31635 being exploited?

It currently carries a trending score of 8 in the Threadlinqs vulnerability feed.

Affected products and versions

Linux: Kernel

How to fix CVE-2026-31635

The record marks a vendor fix as available for CVE-2026-31635. Patch reference: https://git.kernel.org/stable/c/e2f1a80d8b1ed6a5ae585a399c2b46500bdcc305. 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-2026-31635

1 tracked threat in the Threadlinqs corpus references CVE-2026-31635, either in the campaign’s CVE list or as an indicator on the campaign record.

DirtyDecrypt / DirtyCBC — Linux Kernel rxgk Root LPE with Public PoC (CVE-2026-31635) — HIGH · 2026-05-18

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-2026-31635 are available via the Threadlinqs MCP server (Purple tier). View plans →

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