cbcvebase.
CVE-2025-68259
published 2025-12-16

CVE-2025-68259: In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Don't skip unrelated instruction if INT3/INTO is replaced When re-injecting a…

PriorityP422high7.2
EPSS
0.17%
6.7th percentile
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Don't skip unrelated instruction if INT3/INTO is replaced When re-injecting a soft interrupt from an INT3, INT0, or (select) INTn instruction, discard the exception and retry the instruction if the code stream is changed (e.g. by a different vCPU) between when the CPU executes the instruction and when KVM decodes the instruction to get the next RIP. As effectively predicted by commit 6ef88d6e36c2 ("KVM: SVM: Re-inject INT3/INTO instead of retrying the instruction"), failure to verify that the correct INTn instruction was decoded can effectively clobber guest state due to decoding the wrong instruction and thus specifying the wrong next RIP. The bug most often manifests as "Oops: int3" panics on static branch checks in Linux guests. Enabling or disabling a static branch in Linux uses the kernel's "text poke" code patching mechanism. To modify code while other CPUs may be executing that code, Linux (temporarily) replaces the first byte of the original instruction with an int3 (opcode 0xcc), then patches in the new code stream except for the first byte, and finally replaces the int3 with the first byte of the new code stream. If a CPU hits the int3, i.e. executes the code while it's being modified, then the guest kernel must look up the RIP to determine how to handle the #BP, e.g. by emulating the new instruction. If the RIP is incorrect, then this lookup fails and the guest kernel panics. The bug reproduces almost instantly by hacking the guest kernel to repeatedly check a static branch[1] while running a drgn script[2] on the host to constantly swap out the memory containing the guest's TSS. [1]: https://gist.github.com/osandov/44d17c51c28c0ac998ea0334edf90b5a [2]: https://gist.github.com/osandov/10e45e45afa29b11e0c7209247afc00b

Affected

41 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.162-1 (bookworm)linux 6.1.162-1 (bookworm)
debianlinux-6.1< linux 6.1.162-1 (bookworm)linux 6.1.162-1 (bookworm)
linuxlinux
linuxlinux>= 6ef88d6e36c2b4b3886ec9967cafabe4424d27d5 < 2e84a018c2895c05abe213eb10db128aa45f6ec62e84a018c2895c05abe213eb10db128aa45f6ec6
linuxlinux>= 6ef88d6e36c2b4b3886ec9967cafabe4424d27d5 < 152289a51107ef45bbfe9b4aeeaa584a503042b5152289a51107ef45bbfe9b4aeeaa584a503042b5
linuxlinux>= 6ef88d6e36c2b4b3886ec9967cafabe4424d27d5 < 87cc1622c88a4888959d64fa1fc9ba1e264aa3d487cc1622c88a4888959d64fa1fc9ba1e264aa3d4
linuxlinux>= 6ef88d6e36c2b4b3886ec9967cafabe4424d27d5 < 54bcccc2c7805a00af1d7d2faffd6f424c0133aa54bcccc2c7805a00af1d7d2faffd6f424c0133aa
linuxlinux>= 6ef88d6e36c2b4b3886ec9967cafabe4424d27d5 < 53903ac9ca1abffa27327e85075ec496fa55ccf353903ac9ca1abffa27327e85075ec496fa55ccf3
linuxlinux>= 6ef88d6e36c2b4b3886ec9967cafabe4424d27d5 < 4da3768e1820cf15cced390242d8789aed34f54d4da3768e1820cf15cced390242d8789aed34f54d
linuxlinux_kernel>= 0 < 6.1.162-16.1.162-1
linuxlinux_kernel>= 0 < 6.12.63-16.12.63-1
linuxlinux_kernel>= 0 < 6.17.12-16.17.12-1
linuxlinux_kernel>= 0 < 6.17.0-19.196.17.0-19.19
linuxlinux_kernel>= 6.0.0 < 6.1.1606.1.160
linuxlinux_kernel>= 6.13.0 < 6.17.126.17.12
linuxlinux_kernel>= 6.18.0 < 6.18.16.18.1
linuxlinux_kernel>= 6.2.0 < 6.6.1206.6.120
linuxlinux_kernel>= 6.7.0 < 6.12.626.12.62
msrcazl3_kernel_6.6.117.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.119.3-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.119.3-3_on_azure_linux_3.0
ubuntulinux-aws-fips
ubuntulinux-azure
ubuntulinux-azure-6.8
ubuntulinux-azure-fips

CVSS provenance

osv7.2HIGH
vendor_ubuntu7.2HIGH
vendor_msrc6.2MEDIUM
vendor_redhat5.5MEDIUM
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