sctp: stop processing a packet once its association is deleted
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 9 fixed, 6 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: sctp: stop processing a packet once its association is deleted sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is NULL, and caches the result in chunk->asoc and chunk->transport without taking a reference. A packet that matches no association is handed to the endpoint, so a peer can bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The COOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and with the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(), so the association and its transports are freed. The endpoint loop has no counterpart to the asoc->base.dead check in sctp_assoc_bh_rcv(). The next chunk writes to last_time_heard in the freed transport and is then passed to sctp_do_sm() with the freed association. The transport is freed through RCU, so this needs the packet to come off the socket backlog, where the loop runs in task context. The endpoint loop cannot do the same check: it holds no reference on the association, so reading asoc->base.dead would itself be a use-after-free. Mark the packet for discard in the command interpreter, just before it deletes the association. That is also before sctp_inq_free() releases the chunk on the association receive path. sctp_sf_do_5_2_4_dupcook() issues SCTP_CMD_DELETE_TCB for the temporary association, while the one the packet belongs to stays alive. A restarting peer can bundle DATA behind its COOKIE ECHO, so compare against chunk->asoc and leave that case alone.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.12 and later | 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.12 and later Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
Red Hat 3 advisories
- RHSA-2026:95370 Released 2026-11-05 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.66.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.66.1.el9_8, kernel-64k-devel-5.14.0-687.66.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.66.1.el9_8, kernel-64k-5.14.0-687.66.1.el9_8, kernel-64k-core-5.14.0-687.66.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.66.1.el9_8, libperf-5.14.0-687.66.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.66.1.el9_8, kernel-rt-64k-5.14.0-687.66.1.el9_8, kernel-rt-64k-core-5.14.0-687.66.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.66.1.el9_8, kernel-rt-core-5.14.0-687.66.1.el9_8, kernel-rt-debug-5.14.0-687.66.1.el9_8 +9
- RHSA-2026:85773 Released 2026-10-20 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.176.1.el8_10, kernel-4.18.0-553.176.1.el8_10, kernel-abi-stablelists-4.18.0-553.176.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.176.1.el8_10
- RHSA-2026:85774 Released 2026-10-20 · Red Hat rating Importantkernel-rt security, bug fix, and enhancement update
- Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-core-4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-debug-4.18.0-553.176.1.rt7.517.el8_10 +9
- Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-core-4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-debug-4.18.0-553.176.1.rt7.517.el8_10 +7
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | — |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:95370 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:85773 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:95370 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:85773 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:95370 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:85774 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:85774 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:95370 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:95370 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89479
- 2026-10-03 Alias added: GHSA-2f22-4vgf-p33p
- 2026-10-05 EPSS moved to the below the 50th percentile
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-20 Fix available: RHSA-2026:85773 · Red Hat
- 2026-10-20 Fix available: RHSA-2026:85774 · Red Hat
- 2026-10-20 Fix available: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8), Red Hat Enterprise Linux NFV (v. 8) +1 · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-03 CVSS score changed · Red Hat
- 2026-11-05 Fix available: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) +2 · Red Hat
- 2026-11-06 Fix available: RHSA-2026:95370 · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/7d970353eeb98f46a3b9dc602850e4f6336a9889
- https://git.kernel.org/stable/c/09c3b193a3e8fe53e1f416e2f8e3283d2a785405
- https://git.kernel.org/stable/c/ed85fe91a61bc0e0da6b585c07102b20f4cc65a0
- https://git.kernel.org/stable/c/5c0b2dbbdafc9eeeb11fffe1e46551fc3b55d8ee
- https://git.kernel.org/stable/c/ee3f04cf566f6041aa9a0360494fd8db5ade383a
- https://git.kernel.org/stable/c/fa306a40e716c5abcd967475459ce1ebd56e5115
- https://git.kernel.org/stable/c/a713e1b3a265f180ad25a08e17be15d67a2f7149
- https://git.kernel.org/stable/c/47e15a8d12e366d0d261bcbc394394f44418938d
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Sources
- CVE-2026-89479 · CVE Program
- CVE-2026-89479 · NVD
- FIRST EPSS
- GHSA-2f22-4vgf-p33p · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89479 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences