CVE-2026-31635: CVE-2026-31635: In the Linux kernel, the following vulnerability has been resolved: rxrpc: fix oversized …
linux · linux kernel · NVD published 2026-04-24 · posted 2026-05-19 · last modified 2026-06-17
What it is
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.
| Weakness | CWE-130 |
|---|---|
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) |
| ATT&CK tactics | n/a |
Exploitation evidence
First exploit evidence seen: 2026-05-19 (earliest date across the sources below).
Exploited in the wild
No source on this site lists in-the-wild exploitation yet (CISA KEV, VulnCheck KEV).
Public exploit code
GitHub proof-of-concept repositories
3 public repositories from 3 accounts, first seen 2026-05-19. Most starred: 0xBlackash/CVE-2026-31635 (9 stars), view repository.
Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.
Sources: nomi-sec/PoC-in-GitHub.
How to fix it
Fixed versions
- linux linux kernel: upgrade to 6.18.23 or later (affected from 6.16.1)
- linux linux kernel: upgrade to 6.19.13 or later (affected from 6.19)
Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.
Vendor advisories and patches
- https://git.kernel.org/stable/c/a2567217ade970ecc458144b6be469bc015b23e5 (Patch)
- https://git.kernel.org/stable/c/beee051f259acd286fed64c32c2b31e6f5097eb5 (Patch)
- https://git.kernel.org/stable/c/e2f1a80d8b1ed6a5ae585a399c2b46500bdcc305 (Patch)
Detection Generic guidance
Response checklist Generic guidance
- Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
- Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
- Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
- Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.