In the Linux kernel, the following vulnerability has been resolved:
sctp: add INIT verification after cookie unpacking
In SCTP handshake, the INIT chunk is initially processed by the server
and embedded into the cookie carried in INIT-ACK. The client then
returns this cookie via COOKIE-ECHO, where the server unpacks it and
reconstructs the original INIT chunk.
When cookie authentication is enabled, the cookie contents are protected
against tampering, so reusing the unpacked INIT without re-verification
is safe.
However, when cookie authentication is disabled, the reconstructed INIT
can no longer be trusted. In this case, the INIT must be explicitly
validated after unpacking to avoid processing potentially tampered data.
Add sctp_verify_init() checks after cookie unpacking in COOKIE-ECHO
processing paths (sctp_sf_do_5_1D_ce() and sctp_sf_do_5_2_4_dupcook())
when cookie_auth_enable is disabled. On failure, the new association is
freed and the packet is discarded.
Also tighten cookie validation in sctp_unpack_cookie() by verifying the
embedded chunk type is SCTP_CID_INIT before treating it as an INIT
chunk.
Finally, update sctp_verify_init() to validate parameter bounds using
the actual embedded INIT length instead of chunk->chunk_end, since the
INIT stored in COOKIE-ECHO may not span the entire chunk buffer.
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 2026-11-12). 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