Bug 2558257 - CVE-2026-102699 xen: xen: Denial of Service via integer underflow during cache flushing [fedora-all]
Summary: CVE-2026-102699 xen: xen: Denial of Service via integer underflow during cach...
Keywords:
Status: ON_QA
Alias: None
Product: Fedora
Classification: Fedora
Component: xen
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Michael Young
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["1b9a3864-753b-4fcf-9106-4...
Depends On:
Blocks: CVE-2026-102699
TreeView+ depends on / blocked
 
Reported: 2026-10-21 12:29 UTC by Oleg Sushchenko
Modified: 2026-10-31 02:44 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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Description Oleg Sushchenko 2026-10-21 12:29:22 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

[This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]

1) XSA-437 (CVE-2023-34321) addressed issues with overflows in
   calculations involved in guests flushing caches through
   GNTTABOP_cache_flush.  Unfortunately the fix there introduced a
   calculation which may underflow, resulting in a loop which would - at
   least on 64-bit Arm - take excessively long, and which would likely
   eventually crash the hypervisor.

   This is CVE-2026-102699.

2) GNTTABOP_cache_flush may be issued on memory mapped from another
   domain using the grant table interface.  However there was no
   restriction to disallow the use of invalidate-without-clean against
   read-only grant mappings, which may corrupt the granted memory.

   This is CVE-2026-102702.

Comment 1 Fedora Update System 2026-10-30 23:27:35 UTC
FEDORA-2026-2b73a60d2c (xen-4.20.4-4.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-2b73a60d2c

Comment 2 Fedora Update System 2026-10-31 02:44:18 UTC
FEDORA-2026-2b73a60d2c has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-2b73a60d2c`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-2b73a60d2c

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.


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