In the Linux kernel, the following vulnerability has been resolved:
sunrpc: wait for in-flight TLS handshake callback when cancel loses race
When wait_for_completion_interruptible_timeout() in
svc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and
tls_handshake_cancel() then returns false, handshake_complete() has
won the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and
is about to invoke svc_tcp_handshake_done(), but the callback's
side effects on xpt_flags and on svsk->sk_handshake_done have not
yet committed.
The current code reads xpt_flags immediately to decide whether the
session succeeded. Two races result.
If the callback has executed set_bit(XPT_TLS_SESSION) but not yet
clear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session,
enqueues the transport, and returns. svc_xprt_received() then
clears XPT_BUSY, a worker thread picks the transport up, the
dispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set,
and xpo_handshake is invoked a second time. That svc_tcp_handshake()
calls init_completion(&svsk->sk_handshake_done) while the original
callback concurrently calls complete_all() on it, corrupting the
embedded swait_queue.
If the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet
entered svc_tcp_handshake_done(), svc_tcp_handshake() reads
XPT_TLS_SESSION as clear and tears the connection down even though
the handshake is about to succeed.
Wait for the callback to commit before inspecting xpt_flags. The
completion is guaranteed to fire because handshake_complete()
invokes svc_tcp_handshake_done() unconditionally once it has set
HANDSHAKE_F_REQ_COMPLETED.
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
- 0.6% 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