sctp: fix stream->outcnt underflow on duplicate RECONF responses
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 5 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: fix stream->outcnt underflow on duplicate RECONF responses A cached RECONF chunk may contain more than one request parameter. A duplicate response can therefore find and process the same ADD_OUT request again while another parameter is still outstanding, rolling back outcnt twice and possibly underflowing it. Track outstanding request types as bits and clear each bit after its first response. Later responses for the same request are then ignored.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
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
Vendor assessments
Red Hat
Red Hat rating: Moderate. 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 8 | 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 |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89476
- 2026-10-03 Alias added: GHSA-p69r-6fx2-qv4w
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-18 Priority changed: LOW → MEDIUM
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-29 CVSS score changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/041f7df5a929d3e7435dd8387e8ea17f2d412b7d
- https://git.kernel.org/stable/c/59f61c39cb99ee1737bd742a20094fe5653389bb
- https://git.kernel.org/stable/c/793519e343867ee9a3e84f6cac07f81f2aec7b5d
- https://git.kernel.org/stable/c/092acd3c55a4077b00489064615d8d2d898daf91
- https://git.kernel.org/stable/c/2d867663c563e8009257b9edf9c8ec75d9bbf19a
- https://git.kernel.org/stable/c/d02a5794c3deedcb8476d017fcee2b7aaedab2e1
- https://git.kernel.org/stable/c/8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68
- https://git.kernel.org/stable/c/3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e
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Sources
- CVE-2026-89476 · CVE Program
- CVE-2026-89476 · NVD
- FIRST EPSS
- GHSA-p69r-6fx2-qv4w · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89476 · 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