CVE-2020-25597
published 2020-09-23CVE-2020-25597: An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the…
PriorityP424medium6.5CVSS 3.1
AVLACLPRLUINSCCNINAH
EPSS
0.36%
28.1th percentile
An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host. An unprivileged guest may be able to crash Xen, leading to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only systems with untrusted guests permitted to create more than the default number of event channels are vulnerable. This number depends on the architecture and type of guest. For 32-bit x86 PV guests, this is 1023; for 64-bit x86 PV guests, and for all ARM guests, this number is 4095. Systems where untrusted guests are limited to fewer than this number are not vulnerable. Note that xl and libxl limit max_event_channels to 1023 by default, so systems using exclusively xl, libvirt+libxl, or their own toolstack based on libxl, and not explicitly setting max_event_channels, are not vulnerable.
Affected
8 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | xen | < xen 4.14.0+80-gd101b417b7-1 (bookworm) | xen 4.14.0+80-gd101b417b7-1 (bookworm) |
| fedoraproject | fedora | — | — |
| xen | xen | >= 0 < 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
| xen | xen | >= 0 < 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
| xen | xen | >= 0 < 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
| xen | xen | >= 0 < 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
| xen | xen | >= 0 < 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 |
| xen | xen | 4.4.0 – 4.14.0 | — |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
nvdv2.06.1MEDIUMAV:L/AC:L/Au:N/C:P/I:P/A:C
osv6.5MEDIUM
vendor_debian6.5MEDIUM
vendor_redhat6.5MEDIUM
vendor_ubuntu5.5MEDIUM
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Ubuntu
Xen vulnerabilities
vendor_ubuntu·2022-09-19·CVSS 5.5
CVE-2020-25599 [MEDIUM] Xen vulnerabilities
Title: Xen vulnerabilities
Summary: Several security issues were fixed in Xen.
It was discovered that memory contents previously stored in
microarchitectural special registers after RDRAND, RDSEED, and SGX EGETKEY
read operations on Intel client and Xeon E3 processors may be briefly
exposed to processes on the same or different processor cores. A local
attacker could use this to expose sensitive information. (CVE-2020-0543)
Julien Grall discovered that Xen incorrectly handled memory barriers on
ARM-based systems. An attacker could possibly use this issue to cause a
denial of service, obtain sensitive information or escalate privileges.
(CVE-2020-11739)
Ilja Van Sprundel discovered that Xen incorrectly handled profiling of
guests. An unprivileged attacker could use this issue to obtain
Red Hat
xen: once valid event channels may not turn invalid (XSA-338)
vendor_redhat·2020-09-22·CVSS 6.5
CVE-2020-25597 [MEDIUM] CWE-440 xen: once valid event channels may not turn invalid (XSA-338)
xen: once valid event channels may not turn invalid (XSA-338)
An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host. An unprivileged guest may be able to crash Xen, leading to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only systems with untrusted guests permi
Debian
CVE-2020-25597: xen - An issue was discovered in Xen through 4.14.x. There is mishandling of the const...
vendor_debian·2020·CVSS 6.5
CVE-2020-25597 [MEDIUM] CVE-2020-25597: xen - An issue was discovered in Xen through 4.14.x. There is mishandling of the const...
An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host. An unprivileged guest may be able to crash Xen, leading to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only systems with untrusted guests permitted to create more than the default number of event channels a
OSV
xen vulnerabilities
osv·2022-09-19·CVSS 5.5
CVE-2020-0543 [MEDIUM] xen vulnerabilities
xen vulnerabilities
It was discovered that memory contents previously stored in
microarchitectural special registers after RDRAND, RDSEED, and SGX EGETKEY
read operations on Intel client and Xeon E3 processors may be briefly
exposed to processes on the same or different processor cores. A local
attacker could use this to expose sensitive information. (CVE-2020-0543)
Julien Grall discovered that Xen incorrectly handled memory barriers on
ARM-based systems. An attacker could possibly use this issue to cause a
denial of service, obtain sensitive information or escalate privileges.
(CVE-2020-11739)
Ilja Van Sprundel discovered that Xen incorrectly handled profiling of
guests. An unprivileged attacker could use this issue to obtain sensitive
information from other guests, cause a denial of s
GHSA
GHSA-jfr2-c4pw-p2hx: An issue was discovered in Xen through 4
ghsa_unreviewed·2022-05-24
CVE-2020-25597 [MEDIUM] CWE-119 GHSA-jfr2-c4pw-p2hx: An issue was discovered in Xen through 4
An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host. An unprivileged guest may be able to crash Xen, leading to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only systems with untrusted guests permitted to create more than the default number of event channels a
OSV
CVE-2020-25597: An issue was discovered in Xen through 4
osv·2020-09-23·CVSS 6.5
CVE-2020-25597 [MEDIUM] CVE-2020-25597: An issue was discovered in Xen through 4
An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host. An unprivileged guest may be able to crash Xen, leading to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only systems with untrusted guests permitted to create more than the default number of event channels a
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2020-25597 xen: once valid event channels may not turn invalid (XSA-338) [fedora-all]
bugzilla·2020-09-22·CVSS 6.5
CVE-2020-25597 [MEDIUM] CVE-2020-25597 xen: once valid event channels may not turn invalid (XSA-338) [fedora-all]
CVE-2020-25597 xen: once valid event channels may not turn invalid (XSA-338) [fedora-all]
This is an automatically created tracking bug! It was created to ensure
that one or more security vulnerabilities are fixed in affected versions
of fedora-all.
For comments that are specific to the vulnerability please use bugs filed
against the "Security Response" product referenced in the "Blocks" field.
For more information see:
http://fedoraproject.org/wiki/Security/TrackingBugs
When submitting as an update, use the fedpkg template provided in the next
comment(s). This will include the bug IDs of this tracking bug as well as
the relevant top-level CVE bugs.
Please also mention the CVE IDs being fixed in the RPM changelog and the
fedpkg commit message.
NOTE: this issue affects multiple suppor
Bugzilla
CVE-2020-25597 xen: once valid event channels may not turn invalid (XSA-338)
bugzilla·2020-09-16·CVSS 6.5
CVE-2020-25597 [MEDIUM] CVE-2020-25597 xen: once valid event channels may not turn invalid (XSA-338)
CVE-2020-25597 xen: once valid event channels may not turn invalid (XSA-338)
Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host.
Discussion:
Acknowledgments:
Name: the Xen project
---
Mitigation:
The issue can be avoided by reducing the number of event channels available to the guest to no more than 1023. For example, setting `max_event_channels=1023` in the xl domain configuration, or deleting any existing setting (since 1023 is the default for xl/libxl).
For ARM systems, any limit no mo
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/https://security.gentoo.org/glsa/202011-06https://www.debian.org/security/2020/dsa-4769https://xenbits.xen.org/xsa/advisory-338.htmlhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/https://security.gentoo.org/glsa/202011-06https://www.debian.org/security/2020/dsa-4769https://xenbits.xen.org/xsa/advisory-338.html
2020-09-23
Published