UBUNTU-CVE-2026-74610: Null Pointer Dereference
In the Linux kernel, the following vulnerability has been resolved: tls: don't leave a full plaintext skmsg ring unpushed When the copy path in tlsswsendmsglocked() adds the fragment that fills the plaintext skmsg ring, it does not set fullrecord, so the record is left full and unpushed. A later splice() then adds to an already full ring: skmsgpageadd() has no fullness check of its own, so sg.end wraps onto sg.start and the ring appears empty. Fragments added after that overwrite live entries, and sg.size no longer matches what is reachable between sg.start and sg.end, so pushing the record runs the scatterwalk off the end of the scatterlist. An unprivileged user can trigger this on a loopback TCP socket with the "tls" ULP attached: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:memcpyfromscatterwalk+0x32/0xc0 Call Trace: skcipherwalknext+0x1d1/0x2c0 gcmencryptaesniavx+0x1e9/0x220 bpfexectxverdict+0x3bb/0x860 tlsswsendmsg+0xa1a/0xca0 syssendto+0x1da/0x1f0 Set fullrecord in the copy path when the ring becomes full, and push a record that is already full on entry to the sendmsg loop.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1036.39 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
Who can trigger this vulnerability?
An unprivileged local user can trigger it using a loopback TCP socket with the TLS ULP attached. The attack vector is local and requires low privileges; no user interaction is required.
What conditions are needed for exploitation?
The vulnerable path involves filling the plaintext sk_msg ring through the TLS software send path, then using splice() after the ring is already full. This can cause ring state corruption and a scatterlist overrun when the record is pushed.
What is the likely impact?
The reported outcome is a kernel NULL pointer dereference during encryption-related scatterwalk processing. The supplied severity vector rates confidentiality, integrity, and availability impacts as high.
Which Ubuntu kernel packages are identified as affected?
The affected software list includes ubuntu/linux-riscv, ubuntu/linux-realtime, ubuntu/linux-azure, ubuntu/linux-gcp, ubuntu/linux-azure-fde, ubuntu/linux-gke, ubuntu/linux-hwe-edge, and ubuntu/linux-gkeop.