CVE-2026-72385: tracing/fprobe: Fix NULL pointer dereference in fprobe_fgraph_entry()
In the Linux kernel, the following vulnerability has been resolved:
tracing/fprobe: Fix NULL pointer dereference in fprobefgraphentry()
fprobefgraphentry() sizes a shadow-stack reservation in one walk of the per-ip fprobe list and fills it in a second walk, both under rcureadlock() only. A fprobe registered on an already-live ip can become visible between the two walks, so the fill walk processes an exithandler the sizing walk did not count and used runs past reservedwords. If the sizing walk counted nothing, fgraphdata is NULL and the first writefprobeheader() faults:
Oops: general protection fault, probably for non-canonical address ... KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:fprobefgraphentry+0xa38/0xf10 kernel/trace/fprobe.c:167 Call Trace: <TASK> functiongraphenterregs+0x44c/0xa10 kernel/trace/fgraph.c:677 ftracegraphfunc+0xc5/0x140 arch/x86/kernel/ftrace.c:671 kerneltextaddress+0x9/0x40 kernel/extable.c:78 archstackwalk+0x117/0x170 arch/x86/kernel/stacktrace.c:26 kmemcachefree+0x188/0x580 mm/slub.c:6378 tcpdataqueue+0x18d/0x6550 net/ipv4/tcpinput.c:5590 [...] </TASK>
The list cannot be frozen across the two walks, so skip a node that does not fit the reservation and count it as missed.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
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ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-38.38 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Compensating control
In fprobe_fgraph_entry(), during the fill walk, skip any fprobe node that does not fit the shadow-stack reservation and count it as missed; ensure no write_fprobe_header() occurs when the sizing walk counted nothing and fgraph_data is NULL.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72385?
CVE-2026-72385 has a risk rating of 23, indicating a significant security concern.
How do I fix CVE-2026-72385?
To fix CVE-2026-72385, ensure that your Linux kernel is updated to the latest stable version that addresses this vulnerability.
What impact does CVE-2026-72385 have on my system?
CVE-2026-72385 can lead to a NULL pointer dereference, which may cause a denial of service or system instability.
Is CVE-2026-72385 being actively exploited?
There is currently no public record of active exploitation for CVE-2026-72385, but it is advisable to apply patches promptly.
What versions of the Linux kernel are affected by CVE-2026-72385?
CVE-2026-72385 affects specific versions of the Linux kernel prior to the release that includes the fix for this vulnerability.