Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: net: sock: fix hardened usercopy panic in sock_recv_errqueue skbuff_fclone_cache… (CVE-2026-22977)
A vulnerability in the Linux kernel's networking subsystem involving hardened usercopy was resolved. The flaw caused a kernel panic when CONFIG_HARDENED_USERCOPY was enabled due to missing usercopy whitelist definitions in skbuff_fclone_cache. This led to a BUG() during copying of socket error queue data to userspace. The issue affects multiple Linux kernel versions prior to specific patched releases and has been fixed in updated kernel packages. The vulnerability has a medium severity score and no known exploits in the wild. Users should apply the official patches and reboot to mitigate the issue.
AI Analysis
Technical Summary
CVE-2026-22977 is a vulnerability in the Linux kernel networking code where skbuff_fclone_cache was created without defining a usercopy whitelist region, unlike skbuff_head_cache. When CONFIG_HARDENED_USERCOPY is enabled, this causes a kernel panic (BUG()) during the copying of sk_buff.cb data to userspace via sock_recv_errqueue() and put_cmsg(). The crash occurs when TCP allocates an skb using alloc_skb_fclone(), clones it, queues it to sk_error_queue, and userspace reads the error queue. The kernel's __check_heap_object() fails due to the missing usercopy whitelist, causing the panic. This flaw has been fixed in updated Linux kernel versions distributed by Ubuntu and others.
Potential Impact
The vulnerability causes a denial of service via kernel panic when the hardened usercopy feature is enabled and the affected code path is exercised. There is no impact on confidentiality or integrity reported. No known exploits are currently in the wild. The issue affects system stability and availability under specific kernel configurations.
Mitigation Recommendations
An official patch is available and has been released by Ubuntu and other Linux distributors. Users should update their Linux kernel packages to the fixed versions listed in the vendor advisory and reboot their systems to apply the changes. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled after updating. No additional mitigations are required beyond applying the official fix.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: net: sock: fix hardened usercopy panic in sock_recv_errqueue skbuff_fclone_cache… (CVE-2026-22977)
Description
A vulnerability in the Linux kernel's networking subsystem involving hardened usercopy was resolved. The flaw caused a kernel panic when CONFIG_HARDENED_USERCOPY was enabled due to missing usercopy whitelist definitions in skbuff_fclone_cache. This led to a BUG() during copying of socket error queue data to userspace. The issue affects multiple Linux kernel versions prior to specific patched releases and has been fixed in updated kernel packages. The vulnerability has a medium severity score and no known exploits in the wild. Users should apply the official patches and reboot to mitigate the issue.
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]~18.04.1?arch=source&distro=esm-infra/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=esm-infra/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]~18.04.1?arch=source&distro=esm-infra/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 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protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingRun on your own infrastructure? 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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-22977 is a vulnerability in the Linux kernel networking code where skbuff_fclone_cache was created without defining a usercopy whitelist region, unlike skbuff_head_cache. When CONFIG_HARDENED_USERCOPY is enabled, this causes a kernel panic (BUG()) during the copying of sk_buff.cb data to userspace via sock_recv_errqueue() and put_cmsg(). The crash occurs when TCP allocates an skb using alloc_skb_fclone(), clones it, queues it to sk_error_queue, and userspace reads the error queue. The kernel's __check_heap_object() fails due to the missing usercopy whitelist, causing the panic. This flaw has been fixed in updated Linux kernel versions distributed by Ubuntu and others.
Potential Impact
The vulnerability causes a denial of service via kernel panic when the hardened usercopy feature is enabled and the affected code path is exercised. There is no impact on confidentiality or integrity reported. No known exploits are currently in the wild. The issue affects system stability and availability under specific kernel configurations.
Mitigation Recommendations
An official patch is available and has been released by Ubuntu and other Linux distributors. Users should update their Linux kernel packages to the fixed versions listed in the vendor advisory and reboot their systems to apply the changes. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled after updating. No additional mitigations are required beyond applying the official fix.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-22977
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:20.04:LTS","Ubuntu:Pro:FIPS-updates:20.04:LTS","Ubuntu:Pro:FIPS: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"]
- Cvss Version
- 3.1
Threat ID: 6a5b637c2d1edb114c8b544e
Added to database: 07/18/2026, 11:29:00 UTC
Last enriched: 08/22/2026, 21:52:33 UTC
Last updated: 09/10/2026, 19:36:52 UTC
Views: 9
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