In the Linux kernel, the following vulnerability has been resolved:
ixgbevf: fix mailbox API compatibility by negotiating supported features
There was backward compatibility in the terms of mailbox API. Various
drivers from various OSes supporting 10G adapters from Intel portfolio
could easily negotiate mailbox API.
This convention has been broken since introducing API 1.4.
Commit 0062e7cc955e ("ixgbevf: add VF IPsec offload code") added support
for IPSec which is specific only for the kernel ixgbe driver. None of the
rest of the Intel 10G PF/VF drivers supports it. And actually lack of
support was not included in the IPSec implementation - there were no such
code paths. No possibility to negotiate support for the feature was
introduced along with introduction of the feature itself.
Commit 339f28964147 ("ixgbevf: Add support for new mailbox communication
between PF and VF") increasing API version to 1.5 did the same - it
introduced code supported specifically by the PF ESX driver. It altered API
version for the VF driver in the same time not touching the version
defined for the PF ixgbe driver. It led to additional discrepancies,
as the code provided within API 1.6 cannot be supported for Linux ixgbe
driver as it causes crashes.
The issue was noticed some time ago and mitigated by Jake within the commit
d0725312adf5 ("ixgbevf: stop attempting IPSEC offload on Mailbox API 1.5").
As a result we have regression for IPsec support and after increasing API
to version 1.6 ixgbevf driver stopped to support ESX MBX.
To fix this mess add new mailbox op asking PF driver about supported
features. Basing on a response determine whether to set support for IPSec
and ESX-specific enhanced mailbox.
New mailbox op, for compatibility purposes, must be added within new API
revision, as API version of OOT PF & VF drivers is already increased to
1.6 and doesn't incorporate features negotiate op.
Features negotiation mechanism gives possibility to be extended with new
features when needed in the future.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-02). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it