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VulnerabilityPublished Updated

CVE-2026-63923: Linux kernel · octeontx2-af: validate body pcifunc in rvu_mbox_handler_rep_event_notify

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in 4467fa514482bbce82f73788943c815f3d126ab3 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 4467fa514482bbce82f73788943c815f3d126ab3, 2156a29aecfffa2eb7c558255690084efbe9f3b0, 68be0260e2a02ff9b18a8678d5f8d1715fa20138
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade Linux kernel to 4467fa514482bbce82f73788943c815f3d126ab3, 2156a29aecfffa2eb7c558255690084efbe9f3b0 or 68be0260e2a02ff9b18a8678d5f8d1715fa20138.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ b8fea84a0468404fe3b3327ad54d583950be9dec, < 4467fa514482bbce82f73788943c815f3d126ab3
Fixed in
  • 4467fa514482bbce82f73788943c815f3d126ab3
LinuxLinuxAffected
  • ≥ b8fea84a0468404fe3b3327ad54d583950be9dec, < 2156a29aecfffa2eb7c558255690084efbe9f3b0
Fixed in
  • 2156a29aecfffa2eb7c558255690084efbe9f3b0
LinuxLinuxAffected
  • ≥ b8fea84a0468404fe3b3327ad54d583950be9dec, < 68be0260e2a02ff9b18a8678d5f8d1715fa20138
Fixed in
  • 68be0260e2a02ff9b18a8678d5f8d1715fa20138
LinuxLinuxAffected
  • =6.13
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: octeontx2-af: validate body pcifunc in rvu_mbox_handler_rep_event_notify rvu_mbox_handler_rep_event_notify() in drivers/net/ethernet/marvell/ octeontx2/af/rvu_rep.c queues a sender-controlled REP_EVENT_NOTIFY request body verbatim, and rvu_rep_up_notify() then forwards event->pcifunc (the nested body field, distinct from the AF-normalised header pcifunc) into rvu_get_pfvf(), rvu_get_pf() and the AF->PF mailbox device index without any bounds check. A VF attached to a PF that has been put into switchdev representor mode reaches this path: the VF mailbox handler otx2_pfvf_mbox_handler() forwards every message id including MBOX_MSG_REP_EVENT_NOTIFY to AF without an allowlist, and the AF dispatcher rewrites only msg->pcifunc, leaving struct rep_event::pcifunc attacker-controlled. The sibling rvu_mbox_handler_esw_cfg() refuses requests whose header pcifunc is not rvu->rep_pcifunc; this handler has no equivalent gate. An out-of-range body pcifunc selects an &rvu->pf[]/&rvu->hwvf[] element past the allocated array and, for RVU_EVENT_MAC_ADDR_CHANGE, turns into a six-byte attacker-chosen OOB ether_addr_copy() target inside the queued worker; KASAN reports a slab-out-of-bounds write in rvu_rep_wq_handler. Reject malformed requests at the handler entry by gating on is_pf_func_valid(), which is already the canonical PF/VF range check in this driver; expose it via rvu.h so callers in rvu_rep.c can use it instead of open-coding the same range arithmetic.

References

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