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Linux Kernel EUVDEUVD-2026-64375

| CVE-2026-74688 CRITICAL
2026-08-22 Linux GHSA-3vfv-7x6v-8jg6
9.8
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
8.1 HIGH

Remotely reachable via an SCTP peer (AV:N, PR:N) but gated on a teardown-versus-transmit race and non-default SCTP/ASCONF configuration, so AC:H; kernel UAF yields high C/I/A potential.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 25, 2026 - 07:12 vuln.today
CVSS changed
Aug 25, 2026 - 06:22 NVD
9.8 (CRITICAL)
Patch available
Aug 22, 2026 - 16:01 EUVD
CVE Published
Aug 22, 2026 - 15:32 cve.org
CRITICAL 9.8
CVE Published
Aug 22, 2026 - 15:32 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

sctp: clear control chunk transport if it is being removed

sctp_make_heartbeat_ack() caches the destination transport in chunk->transport without taking a reference. When src_out_of_asoc_ok is enabled, the HEARTBEAT ACK may remain queued on control_chunk_list instead of being transmitted immediately.

If the peer transport is removed while the chunk is still queued, sctp_assoc_rm_peer() drops the transport and schedules it for RCU freeing, but only clears cached transport pointers in out_chunk_list. The queued control chunk therefore retains a dangling transport pointer.

Once an ASCONF_ACK clears the suppression and the queued control chunk is transmitted, SCTP dereferences the stale transport pointer, leading to a use-after-free.

Fix this by also clearing chunk->transport for queued control chunks in control_chunk_list when removing the transport.

AnalysisAI

Use-after-free in the Linux kernel's SCTP (Stream Control Transmission Protocol) subsystem allows a remote peer to trigger a dangling transport-pointer dereference on the control chunk queue. The flaw arises because sctp_make_heartbeat_ack() caches a destination transport in chunk->transport without holding a reference; when src_out_of_asoc_ok keeps a HEARTBEAT ACK queued and the peer transport is later torn down, the queued chunk retains a stale pointer that is dereferenced on eventual transmission. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Recon
Establish SCTP association with target
Delivery
Trigger address reconfiguration (ASCONF)
Exploit
Force HEARTBEAT ACK queued via suppression
Install
Cause peer transport removal (freed via RCU)
C2
Send ASCONF_ACK to flush queued chunk
Execute
Kernel dereferences stale transport
Impact
Use-after-free crash or memory corruption

Vulnerability AssessmentAI

Exploitation Requires that the target has the SCTP module loaded and an SCTP association reachable to the attacker, plus SCTP dynamic address reconfiguration (ASCONF/ASCONF_ACK) activity and the src_out_of_asoc_ok delayed-transmission path that keeps a HEARTBEAT ACK queued on control_chunk_list. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The signals are conflicting and warrant a nuanced read. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker establishes an SCTP association with a target host that has SCTP and dynamic address reconfiguration in use, then manipulates path/address state so that a HEARTBEAT ACK stays queued (via the src_out_of_asoc_ok suppression) while the associated peer transport is torn down. A subsequent ASCONF_ACK lifts the suppression and the kernel transmits the queued chunk, dereferencing the freed transport and triggering a use-after-free - most likely crashing the kernel (DoS) and potentially enabling memory disclosure or corruption. …
Remediation Vendor-released patch: upgrade to a fixed stable kernel for your branch - 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, or 7.2 (or later), or apply the corresponding stable commit from git.kernel.org/stable (e.g. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, identify all Linux systems where SCTP is enabled and obtain the vendor patch version for your deployed kernel releases. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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EUVD-2026-64375 vulnerability details – vuln.today

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