CVE-2026-31635: rxrpc: fix oversized RESPONSE authenticator length check
- Is it exploited?
Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of .
VulnCheck KEV lists it since . It cites 1 public report, the first from .
- How likely is exploitation in the next 30 days?
- 1%
Up from 0.6% on .
EPSS score, percentile 63.3 of all scored records. A probability estimated by FIRST, not a report of exploitation.
CISA's SSVC assessment in the CVE record lists exploitation as poc.
- How severe?
- 7.5 High
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 6.16
Unaffected before 6.16; 6.18.23; 6.19.13; 7.0
Source: CISA KEV 2026.10.29, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
Description
rxrpc: fix oversized RESPONSE authenticator length check
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.
Source: CVE List, as of . About the data.
What to do
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
Versions by product, as listed in the CVE record (2 products)
| Status | Versions |
|---|---|
| Affected | from 9d1d2b59341f to before beee051f259a |
| Affected | from 9d1d2b59341f to before e2f1a80d8b1e |
| Affected | from 9d1d2b59341f to before a2567217ade9 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | 6.16 |
| Unaffected | before 6.16 |
| Unaffected | 6.18.23 |
| Unaffected | 6.19.13 |
| Unaffected | 7.0 |
Versions not listed are: affected.
Versions the record lists as unaffected: 6.18.23, 6.19.13, 7.0.
Source: CVE List, as of . About the data.
Weakness
CWE-130
- CWE-130: Improper Handling of Length Parameter Inconsistency
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
References
3
Known exploited Linux vulnerabilities
- CVE-2026-46300: Linux Kernel Missing Initialization of a Variable Vulnerability
- CVE-2025-39682: Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability
- CVE-2025-39964: Linux Kernel Race Condition Vulnerability
- CVE-2026-53266: Linux Kernel Out-of-Bounds Write Vulnerability
- CVE-2026-53362: Linux Kernel Unspecified Vulnerability