CVE-2026-23069: vsock/virtio: fix potential underflow in virtio_transport_get_credit()
In the Linux kernel, the following vulnerability has been resolved:
vsock/virtio: fix potential underflow in virtiotransportgetcredit()
The credit calculation in virtiotransportgetcredit() uses unsigned arithmetic:
ret = vvs->peerbufalloc - (vvs->txcnt - vvs->peerfwdcnt);
If the peer shrinks its advertised buffer (peerbufalloc) while bytes are in flight, the subtraction can underflow and produce a large positive value, potentially allowing more data to be queued than the peer can handle.
Reuse virtiotransporthasspace() which already handles this case and add a comment to make it clear why we are doing that.
[Stefano: use virtiotransporthasspace() instead of duplicating the code] [Stefano: tweak the commit message]
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.13-1 - Upgrade
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ubuntu/linux-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-124.124~22.04.1 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1056.62 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1054.55 - Upgrade
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ubuntu/linux-realtime-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1018.20~24.04.1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1059.65+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1058.61+fips1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23069?
CVE-2026-23069 has been classified as a medium severity vulnerability affecting the Linux kernel.
How do I fix CVE-2026-23069?
To fix CVE-2026-23069, you should update your Linux kernel to the latest version that includes the patched code.
What types of software are affected by CVE-2026-23069?
CVE-2026-23069 affects the Linux kernel, specifically the virtio transport functionality.
What could happen if I don't address CVE-2026-23069?
Failure to address CVE-2026-23069 could lead to potential underflows that may impact system stability and security.
Who is responsible for managing CVE-2026-23069?
The maintainers of the Linux kernel are responsible for managing and resolving the issue identified in CVE-2026-23069.