CVE-2023-46836

NameCVE-2023-46836
DescriptionThe fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative Return Stack Overflow) are not IRQ-safe. It was believed that the mitigations always operated in contexts with IRQs disabled. However, the original XSA-254 fix for Meltdown (XPTI) deliberately left interrupts enabled on two entry paths; one unconditionally, and one conditionally on whether XPTI was active. As BTC/SRSO and Meltdown affect different CPU vendors, the mitigations are not active together by default. Therefore, there is a race condition whereby a malicious PV guest can bypass BTC/SRSO protections and launch a BTC/SRSO attack against Xen.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1056928

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
xen (PTS)buster, buster (security)4.11.4+107-gef32c7afa2-1vulnerable
bullseye4.14.6-1vulnerable
bullseye (security)4.14.5+94-ge49571868d-1vulnerable
bookworm4.17.3+10-g091466ba55-1~deb12u1fixed
trixie, sid4.17.3+36-g54dacb5c02-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
xensourcebuster(unfixed)end-of-life
xensourcebullseye(unfixed)end-of-life
xensourcebookworm4.17.2+76-ge1f9cb16e2-1~deb12u1
xensource(unstable)4.17.2+76-ge1f9cb16e2-11056928

Notes

[bullseye] - xen <end-of-life> (EOLed in Bullseye)
[buster] - xen <end-of-life> (DSA 4677-1)
https://xenbits.xen.org/xsa/advisory-446.html

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