CVE-2025-68768
published 2026-01-13CVE-2025-68768: In the Linux kernel, the following vulnerability has been resolved: inet: frags: flush pending skbs in fqdir_pre_exit() We have been seeing occasional…
PriorityP420medium6.4
EPSS
0.17%
6.4th percentile
In the Linux kernel, the following vulnerability has been resolved:
inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasional deadlocks on pernet_ops_rwsem since
September in NIPA. The stuck task was usually modprobe (often loading
a driver like ipvlan), trying to take the lock as a Writer.
lockdep does not track readers for rwsems so the read wasn't obvious
from the reports.
On closer inspection the Reader holding the lock was conntrack looping
forever in nf_conntrack_cleanup_net_list(). Based on past experience
with occasional NIPA crashes I looked thru the tests which run before
the crash and noticed that the crash follows ip_defrag.sh. An immediate
red flag. Scouring thru (de)fragmentation queues reveals skbs sitting
around, holding conntrack references.
The problem is that since conntrack depends on nf_defrag_ipv6,
nf_defrag_ipv6 will load first. Since nf_defrag_ipv6 loads first its
netns exit hooks run _after_ conntrack's netns exit hook.
Flush all fragment queue SKBs during fqdir_pre_exit() to release
conntrack references before conntrack cleanup runs. Also flush
the queues in timer expiry handlers when they discover fqdir->dead
is set, in case packet sneaks in while we're running the pre_exit
flush.
The commit under Fixes is not exactly the culprit, but I think
previously the timer firing would eventually unblock the spinning
conntrack.
Affected
20 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.18.3-1 (forky) | linux 6.18.3-1 (forky) |
| linux | linux | — | — |
| linux | linux | >= d5dd88794a13c2f24cce31abad7a0a6c5e0ed2db < 22ee4010866da81aeee08e1ea3fddbe418feb212 | 22ee4010866da81aeee08e1ea3fddbe418feb212 |
| linux | linux | >= d5dd88794a13c2f24cce31abad7a0a6c5e0ed2db < 543555954b1ee8d1903a7020324efb41b0c97428 | 543555954b1ee8d1903a7020324efb41b0c97428 |
| linux | linux | >= d5dd88794a13c2f24cce31abad7a0a6c5e0ed2db < c70df25214ac9b32b53e18e6ae3b8f073ffa6903 | c70df25214ac9b32b53e18e6ae3b8f073ffa6903 |
| linux | linux | >= d5dd88794a13c2f24cce31abad7a0a6c5e0ed2db < 006a5035b495dec008805df249f92c22c89c3d2e | 006a5035b495dec008805df249f92c22c89c3d2e |
| linux | linux_kernel | >= 0 < 6.18.3-1 | 6.18.3-1 |
| linux | linux_kernel | >= 5.3.0 < 6.18.3 | 6.18.3 |
| ubuntu | linux-aws | — | — |
| ubuntu | linux-aws-6.17 | — | — |
| ubuntu | linux-azure | — | — |
| ubuntu | linux-azure-6.17 | — | — |
| ubuntu | linux-gcp | — | — |
| ubuntu | linux-gcp-6.17 | — | — |
| ubuntu | linux-hwe-6.17 | — | — |
| ubuntu | linux-oem-6.17 | — | — |
| ubuntu | linux-oracle | — | — |
| ubuntu | linux-oracle-6.17 | — | — |
| ubuntu | linux-raspi | — | — |
| ubuntu | linux-realtime-6.17 | — | — |
CVSS provenance
vendor_ubuntu6.4MEDIUM
vendor_redhat4.4MEDIUM
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Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-05-07·CVSS 6.4
CVE-2025-71149 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality. (CVE-2024-36347)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- MIPS architecture;
- PowerPC architecture;
- User-Mode Linux (UML);
- x86 architecture;
- Block layer subsystem;
- Cryptographic API;
- ACPI drivers;
-
Ubuntu
Linux kernel (Raspberry Pi) vulnerabilities
vendor_ubuntu·2026-05-07·CVSS 6.4
CVE-2025-68781 [MEDIUM] Linux kernel (Raspberry Pi) vulnerabilities
Title: Linux kernel (Raspberry Pi) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality. (CVE-2024-36347)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- MIPS architecture;
- PowerPC architecture;
- User-Mode Linux (UML);
- x86 architecture;
- Block layer subsystem;
- Cryptographic API;
-
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-04-23·CVSS 6.4
CVE-2025-68801 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality.
(CVE-2024-36347)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- MIPS architecture;
- PowerPC architecture;
- User-Mode Linux (UML);
- x86 architecture;
- Block layer subsystem;
- Cryptographic API;
- ACPI drivers;
-
Ubuntu
Linux kernel (GCP) vulnerabilities
vendor_ubuntu·2026-04-17·CVSS 6.4
CVE-2025-68736 [MEDIUM] Linux kernel (GCP) vulnerabilities
Title: Linux kernel (GCP) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality.
(CVE-2024-36347)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- MIPS architecture;
- PowerPC architecture;
- User-Mode Linux (UML);
- x86 architecture;
- Block layer subsystem;
- Cryptographic API;
- ACPI driv
Ubuntu
Linux kernel (Real-time) vulnerabilities
vendor_ubuntu·2026-04-17·CVSS 6.4
CVE-2025-68736 [MEDIUM] Linux kernel (Real-time) vulnerabilities
Title: Linux kernel (Real-time) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality.
(CVE-2024-36347)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- MIPS architecture;
- PowerPC architecture;
- User-Mode Linux (UML);
- x86 architecture;
- Block layer subsystem;
- Cryptographic API;
- ACP
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-04-16·CVSS 6.4
CVE-2025-68736 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality.
(CVE-2024-36347)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- MIPS architecture;
- PowerPC architecture;
- User-Mode Linux (UML);
- x86 architecture;
- Block layer subsystem;
- Cryptographic API;
- ACPI drivers;
-
Red Hat
kernel: inet: frags: flush pending skbs in fqdir_pre_exit()
vendor_redhat·2026-01-13·CVSS 4.4
CVE-2025-68768 [MEDIUM] CWE-833 kernel: inet: frags: flush pending skbs in fqdir_pre_exit()
kernel: inet: frags: flush pending skbs in fqdir_pre_exit()
In the Linux kernel, the following vulnerability has been resolved:
inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasional deadlocks on pernet_ops_rwsem since
September in NIPA. The stuck task was usually modprobe (often loading
a driver like ipvlan), trying to take the lock as a Writer.
lockdep does not track readers for rwsems so the read wasn't obvious
from the reports.
On closer inspection the Reader holding the lock was conntrack looping
forever in nf_conntrack_cleanup_net_list(). Based on past experience
with occasional NIPA crashes I looked thru the tests which run before
the crash and noticed that the crash follows ip_defrag.sh. An immediate
red flag. Scouring thru (de)fragmentation queues reve
Debian
CVE-2025-68768: linux - In the Linux kernel, the following vulnerability has been resolved: inet: frags...
vendor_debian·2025
CVE-2025-68768 CVE-2025-68768: linux - In the Linux kernel, the following vulnerability has been resolved: inet: frags...
In the Linux kernel, the following vulnerability has been resolved: inet: frags: flush pending skbs in fqdir_pre_exit() We have been seeing occasional deadlocks on pernet_ops_rwsem since September in NIPA. The stuck task was usually modprobe (often loading a driver like ipvlan), trying to take the lock as a Writer. lockdep does not track readers for rwsems so the read wasn't obvious from the reports. On closer inspection the Reader holding the lock was conntrack looping forever in nf_conntrack_cleanup_net_list(). Based on past experience with occasional NIPA crashes I looked thru the tests which run before the crash and noticed that the crash follows ip_defrag.sh. An immediate red flag. Scouring thru (de)fragmentation queues reveals skbs sitting around, holding conntrack references. The pr
VulDB
Linux Kernel up to 6.18.2/6.19-rc1 inet fqdir_pre_exit deadlock (Nessus ID 298917 / WID-SEC-2026-0086)
vuldb·2026-06-21
CVE-2025-68768 [CRITICAL] Linux Kernel up to 6.18.2/6.19-rc1 inet fqdir_pre_exit deadlock (Nessus ID 298917 / WID-SEC-2026-0086)
A vulnerability has been found in Linux Kernel up to 6.18.2/6.19-rc1 and classified as critical. This affects the function fqdir_pre_exit of the component inet. The manipulation leads to deadlock.
This vulnerability is referenced as CVE-2025-68768. The attack needs to be initiated within the local network. No exploit is available.
The affected component should be upgraded.
OSV
inet: frags: flush pending skbs in fqdir_pre_exit()
osv·2026-01-13
CVE-2025-68768 inet: frags: flush pending skbs in fqdir_pre_exit()
inet: frags: flush pending skbs in fqdir_pre_exit()
In the Linux kernel, the following vulnerability has been resolved:
inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasional deadlocks on pernet_ops_rwsem since
September in NIPA. The stuck task was usually modprobe (often loading
a driver like ipvlan), trying to take the lock as a Writer.
lockdep does not track readers for rwsems so the read wasn't obvious
from the reports.
On closer inspection the Reader holding the lock was conntrack looping
forever in nf_conntrack_cleanup_net_list(). Based on past experience
with occasional NIPA crashes I looked thru the tests which run before
the crash and noticed that the crash follows ip_defrag.sh. An immediate
red flag. Scouring thru (de)fragmentation queues reveals s
OSV
CVE-2025-68768: In the Linux kernel, the following vulnerability has been resolved: inet: frags: flush pending skbs in fqdir_pre_exit() We have been seeing occasional
osv·2026-01-13
CVE-2025-68768 CVE-2025-68768: In the Linux kernel, the following vulnerability has been resolved: inet: frags: flush pending skbs in fqdir_pre_exit() We have been seeing occasional
In the Linux kernel, the following vulnerability has been resolved: inet: frags: flush pending skbs in fqdir_pre_exit() We have been seeing occasional deadlocks on pernet_ops_rwsem since September in NIPA. The stuck task was usually modprobe (often loading a driver like ipvlan), trying to take the lock as a Writer. lockdep does not track readers for rwsems so the read wasn't obvious from the reports. On closer inspection the Reader holding the lock was conntrack looping forever in nf_conntrack_cleanup_net_list(). Based on past experience with occasional NIPA crashes I looked thru the tests which run before the crash and noticed that the crash follows ip_defrag.sh. An immediate red flag. Scouring thru (de)fragmentation queues reveals skbs sitting around, holding conntrack references. The pr
GHSA
GHSA-6g94-rwcj-hwx9: In the Linux kernel, the following vulnerability has been resolved:
inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasion
ghsa_unreviewed·2026-01-13
CVE-2025-68768 GHSA-6g94-rwcj-hwx9: In the Linux kernel, the following vulnerability has been resolved:
inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasion
In the Linux kernel, the following vulnerability has been resolved:
inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasional deadlocks on pernet_ops_rwsem since
September in NIPA. The stuck task was usually modprobe (often loading
a driver like ipvlan), trying to take the lock as a Writer.
lockdep does not track readers for rwsems so the read wasn't obvious
from the reports.
On closer inspection the Reader holding the lock was conntrack looping
forever in nf_conntrack_cleanup_net_list(). Based on past experience
with occasional NIPA crashes I looked thru the tests which run before
the crash and noticed that the crash follows ip_defrag.sh. An immediate
red flag. Scouring thru (de)fragmentation queues reveals skbs sitting
around, holding conntrack references.
Th
No detection rules found.
No public exploits indexed.
2026-01-13
Published