CVE-2026-23554
Use after free of paging structures in EPT
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.
Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.8
Use after free of paging structures in EPT
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.
Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
CVE-2026-23554- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-367
- Updated
- 2026-11-02
EUVDEUVD-2026-14382
7.8
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.
Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
EUVD-2026-14382- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-h6vw-38xq-3xwx
7.8
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until...
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.
Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
GHSA-h6vw-38xq-3xwx- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-367
- Updated
- 2026-11-02
NVD
7.8
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.
Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
CVE-2026-23554- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-367
- Updated
- 2026-11-02
OSVALPINE-CVE-2026-23554
7.8
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.
Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
ALPINE-CVE-2026-23554- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-23554
7.8
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush. Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
DEBIAN-CVE-2026-23554- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
Show 6 moreShow less
OSVUBUNTU-CVE-2026-23554
7.8
The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush. Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.
- Record
UBUNTU-CVE-2026-23554- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
OSVMGASA-2026-0068 No score
Updated xen packages fix security vulnerability
Use after free of paging structures in EPT. (CVE-2026-23554)
- Record
MGASA-2026-0068- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:10457-1 No score
xen-4.21.1_02-1.1 on GA media
These are all security issues fixed in the xen-4.21.1_02-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:10457-1- Updated
- 2026-11-02
OSVSUSE-SU-2026:0908-1 No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2026-23554: xen: Use after free of paging structures in EPT (bsc#1259247, XSA-480)
- CVE-2026-23555: xen: Xenstored DoS by unprivileged domain (bsc#1259248, XSA-481)
- Record
SUSE-SU-2026:0908-1- Updated
- 2026-11-02
OSVSUSE-SU-2026:1092-1 No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2026-23554: xen: Use after free of paging structures in EPT (bsc#1259247, XSA-480)
- Record
SUSE-SU-2026:1092-1- Updated
- 2026-11-02
OSVSUSE-SU-2026:1093-1 No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2026-23554: xen: Use after free of paging structures in EPT (bsc#1259247, XSA-480)
- CVE-2026-23555: xen: Xenstored DoS by unprivileged domain (bsc#1259248, XSA-481)
- Record
SUSE-SU-2026:1093-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
xenAlpine:v3.20 |
4.17 up to 4.18.5-r5 | 4.18.5-r5 |
xenAlpine:v3.21 |
4.17 up to 4.19.4-r2 | 4.19.4-r2 |
xenAlpine:v3.22 |
4.17 up to 4.20.2-r2 | 4.20.2-r2 |
xenAlpine:v3.23 |
4.17 up to 4.20.2-r2 | 4.20.2-r2 |
xenAlpine:v3.24 |
4.17 up to 4.21.0-r3 | 4.21.0-r3 |
xenDebian: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 less4.17.3+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 |
xenDebian: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 |
xenDebian: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 |
xenMageia:9 |
before 4.17.5-1.git20251028.3.mga9 | 4.17.5-1.git20251028.3.mga9 |
xenSUSE:Linux Enterprise Server 15 SP6-LTSS |
before 4.18.5_12-150600.3.40.1 | 4.18.5_12-150600.3.40.1 |
Show 18 moreShow less
| Package | Affected | Fixed |
|---|---|---|
xenSUSE:Linux Enterprise Server for SAP Applications 15 SP6 |
before 4.18.5_12-150600.3.40.1 | 4.18.5_12-150600.3.40.1 |
xenopenSUSE:Leap 15.6 |
before 4.18.5_12-150600.3.40.1 | 4.18.5_12-150600.3.40.1 |
xenSUSE:Linux Enterprise Micro 5.5 |
before 4.17.6_06-150500.3.62.2 | 4.17.6_06-150500.3.62.2 |
xenSUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS |
before 4.17.6_06-150500.3.62.2 | 4.17.6_06-150500.3.62.2 |
xenSUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS |
before 4.17.6_06-150500.3.62.2 | 4.17.6_06-150500.3.62.2 |
xenSUSE:Linux Enterprise Server 15 SP5-LTSS |
before 4.17.6_06-150500.3.62.2 | 4.17.6_06-150500.3.62.2 |
xenSUSE:Linux Enterprise Server for SAP Applications 15 SP5 |
before 4.17.6_06-150500.3.62.2 | 4.17.6_06-150500.3.62.2 |
xenSUSE:Linux Enterprise Module for Basesystem 15 SP7 |
before 4.20.2_08-150700.3.28.1 | 4.20.2_08-150700.3.28.1 |
xenSUSE:Linux Enterprise Module for Server Applications 15 SP7 |
before 4.20.2_08-150700.3.28.1 | 4.20.2_08-150700.3.28.1 |
xenUbuntu: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 less4.6.0-1ubuntu4.14.6.0-1ubuntu4.24.6.0-1ubuntu4.34.6.5-0ubuntu14.6.5-0ubuntu1.14.6.5-0ubuntu1.24.6.5-0ubuntu1.4 |
None known |
xenUbuntu:18.04:LTS |
All versions, plus listed versions 4.9.0-0ubuntu34.9.0-0ubuntu44.9.2-0ubuntu1 |
None known |
xenUbuntu: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 |
xenUbuntu: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 |
xenUbuntu: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 |
xenUbuntu:25.10 |
All versions, plus listed versions 4.20.0-1ubuntu14.20.0+68-g35cb38b222-1 |
None known |
xenUbuntu: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 |
xenUbuntu: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 |
xenopenSUSE:Tumbleweed |
before 4.21.1_02-1.1 | 4.21.1_02-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-23554 is a high vulnerability (CVSS 7.8) in Xen, published March 17, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. Fixed in xen 4.18.5-r5.
References
xenbits.xenproject.org/xsa/advisory-480.html
openwall.com/lists/oss-security/2026/03/17/6
xenbits.xen.org/xsa/advisory-480.html
nvd.nist.gov/vuln/detail/CVE-2026-23554
github.com/advisories/GHSA-h6vw-38xq-3xwx
security.alpinelinux.org/vuln/CVE-2026-23554
Show 12 moreShow less
security-tracker.debian.org/tracker/CVE-2026-23554
advisories.mageia.org/MGASA-2026-0068.html
bugs.mageia.org/show_bug.cgi?id=35222
suse.com/support/update/announcement/2026/suse-su-20260908-1
bugzilla.suse.com/1259247
bugzilla.suse.com/1259248
suse.com/security/cve/CVE-2026-23554
suse.com/security/cve/CVE-2026-23555
suse.com/support/update/announcement/2026/suse-su-20261092-1
suse.com/support/update/announcement/2026/suse-su-20261093-1
ubuntu.com/security/CVE-2026-23554
cve.org/CVERecord?id=CVE-2026-23554