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CVE-2026-23556

oxenstored keeps quota related use counts across domain destruction

9.4 CriticalFix available

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.

When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.14%Unchanged since Jul 10, 2026
90%50%10%1%

What each source reports

CVE List Score used 9.4

oxenstored keeps quota related use counts across domain destruction

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.

When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
CVE-2026-23556
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Weakness
CWE-281
Updated
2026-11-02
EUVDEUVD-2026-42600 9.4

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.

When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
EUVD-2026-42600
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-qcp2-2xf6-hw26 9.4

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are...

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.

When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
GHSA-qcp2-2xf6-hw26
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness
CWE-281
Updated
2026-11-02
NVD 9.4

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.

When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
CVE-2026-23556
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness
CWE-281
Updated
2026-11-02
OSVALPINE-CVE-2026-23556 9.4

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.

When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
ALPINE-CVE-2026-23556
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated
2026-11-02
OSVDEBIAN-CVE-2026-23556 9.4

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked. When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
DEBIAN-CVE-2026-23556
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated
2026-11-02
OSVUBUNTU-CVE-2026-23556 9.4

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked. When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Record
UBUNTU-CVE-2026-23556
CVSS 4.0
9.4 CriticalCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
xen
Debian:12
 before 4.17.7-0+deb12u1, plus listed versions
4.17.1+2-gb773c48e36-14.17.2+55-g0b56bed864-14.17.2+76-ge1f9cb16e2-14.17.2+76-ge1f9cb16e2-1~deb12u14.17.2-1
Show 9 moreShow less
4.17.3+10-g091466ba55-14.17.3+10-g091466ba55-1.14.17.3+10-g091466ba55-1.1~exp14.17.3+10-g091466ba55-1.1~exp24.17.3+10-g091466ba55-1~deb12u14.17.3+36-g54dacb5c02-14.17.5+23-ga4e5191dc0-14.17.5+23-ga4e5191dc0-1+deb12u14.17.5+72-g01140da4e8-1
4.17.7-0+deb12u1
xen
Debian:13
 before 4.20.3+127-gc42374a105-0+deb13u1, plus listed versions
4.20.0+68-g35cb38b222-14.20.2+37-g61ff35323e-0+deb13u14.20.2+37-g61ff35323e-14.20.2+7-g1badcf5035-0+deb13u14.20.2+7-g1badcf5035-14.20.2+7-g1badcf5035-2
4.20.3+127-gc42374a105-0+deb13u1
xen
Debian:14
 before 4.20.3+127-gc42374a105-1, plus listed versions
4.20.0+68-g35cb38b222-14.20.2+37-g61ff35323e-14.20.2+7-g1badcf5035-14.20.2+7-g1badcf5035-2
4.20.3+127-gc42374a105-1
xen
Ubuntu:16.04:LTS
 All versions, plus listed versions
4.5.1-0ubuntu14.5.1-0ubuntu24.6.0-1ubuntu14.6.0-1ubuntu24.6.0-1ubuntu4
Show 7 moreShow less
4.6.0-1ubuntu4.14.6.0-1ubuntu4.24.6.0-1ubuntu4.34.6.5-0ubuntu14.6.5-0ubuntu1.14.6.5-0ubuntu1.24.6.5-0ubuntu1.4
 None known
xen
Ubuntu:18.04:LTS
 All versions, plus listed versions
4.9.0-0ubuntu34.9.0-0ubuntu44.9.2-0ubuntu1
 None known
xen
Ubuntu:20.04:LTS
 All versions, plus listed versions
4.9.2-0ubuntu24.9.2-0ubuntu64.9.2-0ubuntu74.11.3+24-g14b62ab3e5-1ubuntu14.11.3+24-g14b62ab3e5-1ubuntu24.11.3+24-g14b62ab3e5-1ubuntu2.24.11.3+24-g14b62ab3e5-1ubuntu2.3
 None known
xen
Ubuntu:22.04:LTS
 All versions, plus listed versions
4.11.4+24-gddaaccbbab-1ubuntu24.16.0-1~ubuntu24.16.0-1~ubuntu2.1
 None known
xen
Ubuntu:24.04:LTS
 All versions, plus listed versions
4.17.2-14.17.2+55-g0b56bed864-14.17.2+76-ge1f9cb16e2-14.17.2+76-ge1f9cb16e2-1ubuntu14.17.3+10-g091466ba55-14.17.3+10-g091466ba55-1.1ubuntu24.17.3+10-g091466ba55-1.1ubuntu3
 None known
xen
Ubuntu:25.10
 All versions, plus listed versions
4.20.0-1ubuntu14.20.0+68-g35cb38b222-1
 None known
xen
Ubuntu:26.10
 All versions, plus listed versions
4.20.2+7-g1badcf5035-2build24.20.2+37-g61ff35323e-1ubuntu14.20.3+127-gc42374a105-1
 None known
xen
Ubuntu:26.04:LTS
 All versions, plus listed versions
4.20.0+68-g35cb38b222-14.20.2+7-g1badcf5035-24.20.2+7-g1badcf5035-2build2
 None known

History

History
RecordedChangedSources
affected
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-23556 is a critical vulnerability (CVSS 9.4) in Xen Oxenstored, published July 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.14%, the 3rd percentile. Fixed in xen 4.17.7-0+deb12u1.

References

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