CVE-2026-31635
Vulnerability Summary
Timeline
Description
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.
CVSS Metrics
- v4.0•MEDIUM•Score: 6.9CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Trends
Current EPSS score: 0.92%• Percentile: 59%
Techniques & Countermeasures
- CWE-130•Improper Handling of Length Parameter Inconsistency
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Affected Systems
- debian•linux
< 6.19.13-1
- ubuntu•linux
< 6.17.0-40.40
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
< 6.17.0-1019.19
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.14
all
- ubuntu•linux-aws-6.17
< 6.17.0-1019.19~24.04.1
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-azure
all | all
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.11
all
- ubuntu•linux-azure-6.17
< 6.17.0-1021.21~24.04.1
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | all | all
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fde-7.0
all
- ubuntu•linux-bluefield
all
- ubuntu•linux-gcp
all | < 6.17.0-1020.22
- ubuntu•linux-gcp-5.11
all
- ubuntu•linux-gcp-5.13
all
- ubuntu•linux-gcp-5.19
all
- ubuntu•linux-gcp-5.3
all
- ubuntu•linux-gcp-5.8
all
- ubuntu•linux-gcp-6.11
all
- ubuntu•linux-gcp-6.14
all
- ubuntu•linux-gcp-6.17
< 6.17.0-1020.22~24.04.1
- ubuntu•linux-gcp-6.2
all
- ubuntu•linux-gcp-6.5
all
- ubuntu•linux-gke
all
- ubuntu•linux-gke-4.15
all
- ubuntu•linux-gke-5.15
all
- ubuntu•linux-gke-5.4
all
- ubuntu•linux-gkeop
all
- ubuntu•linux-gkeop-5.15
all
- ubuntu•linux-gkeop-5.4
all
- ubuntu•linux-hwe
all
- ubuntu•linux-hwe-5.11
all
Showing first 50 affected entries in server-rendered view.
References (16)
- https://git.kernel.org/stable/c/beee051f259acd286fed64c32c2b31e6f5097eb5
- https://git.kernel.org/stable/c/e2f1a80d8b1ed6a5ae585a399c2b46500bdcc305
- https://git.kernel.org/stable/c/a2567217ade970ecc458144b6be469bc015b23e5
- https://github.com/v12-security/pocs/tree/main/dirtydecrypt
- https://ubuntu.com/security/CVE-2026-31635
- https://www.cve.org/CVERecord?id=CVE-2026-31635
- https://git.kernel.org/linus/a2567217ade970ecc458144b6be469bc015b23e5
- https://ubuntu.com/security/notices/USN-8490-1
- https://ubuntu.com/security/notices/USN-8491-1
- https://ubuntu.com/security/notices/USN-8508-1
- https://ubuntu.com/security/notices/USN-8490-2
- https://ubuntu.com/security/notices/USN-8545-1
- https://ubuntu.com/security/notices/USN-8546-1
- https://ubuntu.com/security/notices/USN-8604-1
- https://ubuntu.com/security/notices/USN-8605-1
- https://security-tracker.debian.org/tracker/CVE-2026-31635