Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: ADD_ADDR rtx: free sk if last When an ADD_ADDR is retransmitted, the… (CVE-2026-46170)
A medium severity vulnerability (CVE-2026-46170) in the Linux kernel's Multipath TCP (MPTCP) implementation was resolved. The issue involves improper handling of socket references during retransmission of ADD_ADDR messages, which could cause indefinite waiting in the timer handler and potentially lead to denial of service. Multiple Linux kernel versions prior to 7.0.0-28.28 and related builds are affected. A patch is available and included in updated Ubuntu kernel packages. Users should update and reboot to apply the fix.
AI Analysis
Technical Summary
CVE-2026-46170 addresses a flaw in the Linux kernel's Multipath TCP path manager where retransmitted ADD_ADDR messages cause improper socket reference handling. Specifically, when an ADD_ADDR is retransmitted, the socket is held in sk_reset_timer() and released at the end. If this is the last reference, the socket is not freed correctly, leading to a call to sk_stop_timer_sync() on the same timer, causing indefinite waiting. The fix involves marking the timer as done at the end of the handler to prevent this deadlock. This vulnerability affects multiple Linux kernel versions prior to 7.0.0-28.28 and related builds distributed by Ubuntu. The issue has a CVSS 3.1 score of 5.5 (medium severity) with local attack vector, low complexity, requiring low privileges and no user interaction, impacting availability only.
Potential Impact
The vulnerability can cause a denial of service condition by causing indefinite waiting in the kernel timer handler due to improper socket reference management during ADD_ADDR retransmission in Multipath TCP. There is no impact on confidentiality or integrity. The attack requires local access with low privileges and no user interaction. No known exploits are reported in the wild.
Mitigation Recommendations
An official patch is available and included in updated Ubuntu Linux kernel packages. Users should apply the kernel updates to versions 7.0.0-28.28 or later (and corresponding patched builds) and reboot their systems to complete remediation. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled after the update. No additional mitigation steps are required beyond applying the official fix.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: ADD_ADDR rtx: free sk if last When an ADD_ADDR is retransmitted, the… (CVE-2026-46170)
Description
A medium severity vulnerability (CVE-2026-46170) in the Linux kernel's Multipath TCP (MPTCP) implementation was resolved. The issue involves improper handling of socket references during retransmission of ADD_ADDR messages, which could cause indefinite waiting in the timer handler and potentially lead to denial of service. Multiple Linux kernel versions prior to 7.0.0-28.28 and related builds are affected. A patch is available and included in updated Ubuntu kernel packages. Users should update and reboot to apply the fix.
CVSS v3.1
Score 5.5medium
Affected software
pkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.2?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]+cvm1.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.3?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email 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protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-46170 addresses a flaw in the Linux kernel's Multipath TCP path manager where retransmitted ADD_ADDR messages cause improper socket reference handling. Specifically, when an ADD_ADDR is retransmitted, the socket is held in sk_reset_timer() and released at the end. If this is the last reference, the socket is not freed correctly, leading to a call to sk_stop_timer_sync() on the same timer, causing indefinite waiting. The fix involves marking the timer as done at the end of the handler to prevent this deadlock. This vulnerability affects multiple Linux kernel versions prior to 7.0.0-28.28 and related builds distributed by Ubuntu. The issue has a CVSS 3.1 score of 5.5 (medium severity) with local attack vector, low complexity, requiring low privileges and no user interaction, impacting availability only.
Potential Impact
The vulnerability can cause a denial of service condition by causing indefinite waiting in the kernel timer handler due to improper socket reference management during ADD_ADDR retransmission in Multipath TCP. There is no impact on confidentiality or integrity. The attack requires local access with low privileges and no user interaction. No known exploits are reported in the wild.
Mitigation Recommendations
An official patch is available and included in updated Ubuntu Linux kernel packages. Users should apply the kernel updates to versions 7.0.0-28.28 or later (and corresponding patched builds) and reboot their systems to complete remediation. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled after the update. No additional mitigation steps are required beyond applying the official fix.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-46170
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:Nvidia-BlueField:22.04:LTS","Ubuntu:Pro:FIPS-preview:22.04:LTS","Ubuntu:Pro:FIPS-updates:22.04:LTS","Ubuntu:Pro:Realtime:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:Nvidia-BlueField:24.04:LTS","Ubuntu:Pro:FIPS-updates:24.04:LTS","Ubuntu:Pro:Realtime:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6a5a01e291ae9bcd3f82e931
Added to database: 07/17/2026, 10:20:18 UTC
Last enriched: 09/08/2026, 00:32:25 UTC
Last updated: 09/14/2026, 22:01:34 UTC
Views: 18
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