In the Linux kernel, the following vulnerability has been resolved:
nvmet-auth: reject short AUTH_RECEIVE buffers
nvmet_execute_auth_receive() trusts the AUTH_RECEIVE allocation length
after checking only that it is nonzero and matches the transfer length.
In the SUCCESS1 and FAILURE1/default states, that lets a remote NVMe-oF
initiator reach the fixed-size DH-HMAC-CHAP response builders with a
kmalloc() buffer shorter than the response, so nvmet_auth_success1() and
nvmet_auth_failure1() write past the allocation; both only WARN_ON the
short length and then format the message anyway.
Impact: A remote NVMe-oF initiator with access to an auth-enabled target
can trigger a 16-byte heap out-of-bounds write via a one-byte
AUTH_RECEIVE allocation length.
Compute the minimum response length for the current DH-HMAC-CHAP step in
nvmet_auth_receive_data_len() and report a zero data length when the
host-supplied allocation length is shorter, so the existing zero-length
check in nvmet_execute_auth_receive() rejects the command before any
builder runs. The SUCCESS1 minimum is sizeof(struct
nvmf_auth_dhchap_success1_data) plus the HMAC hash length, because the
response hash is written into the rval[] flexible-array tail, so the
minimum is state dependent rather than a flat sizeof. CHALLENGE keeps its
existing variable-length guard in nvmet_auth_challenge().
This is reachable only when in-band DH-HMAC-CHAP authentication is
configured on the target.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). 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; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days 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; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (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)3 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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