The set_debugreg hypercall in include/asm-x86/debugreg.h in Xen 4.0, 4.1, and 4.2, and Citrix XenServer 6.0.2 and earlier, when running on x
The set_debugreg hypercall in include/asm-x86/debugreg.h in Xen 4.0, 4.1, and 4.2, and Citrix XenServer 6.0.2 and earlier, when running on x86-64 systems, allows local OS guest users to cause a denial of service (host crash) by writing to the reserved bits of the DR7 debug control register.
- Published
- Nov 23, 2012
- Updated
- Jun 16, 2026
- EPSS
- 0.4% · 36th percentile
- CWE
- CWE-264
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
8
Monitor
Low priority for now.
- CVSS
- 8 / 40 · 2.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
Affected systems
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- citrix xenserverup to 6.0.2 inclusive
- xen xen4.0.0
- xen xen4.1.0
- xen xen4.2.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | xen | before 4.1.3-2 | 4.1.3-2 |
| Debian:6.0 | xen | before 4.0.1-5.4 | 4.0.1-5.4 |
Same product
citrix: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-14007Citrix XenServer 7.1 and newer allows Directory Traversal.56Plan
- CVE-2014-4947Buffer overflow in the HVM graphics console support in Citrix XenServer 6.2 Service Pack 1 and earlier has unspecified impact and attack vec42Plan
- CVE-2016-5302Citrix XenServer 7.0 before Hotfix XS70E003, when a deployment has been upgraded from an earlier release, might allow remote attackers on th40Plan
- CVE-2012-4606Citrix XenServer 4.1, 6.0, 5.6 SP2, 5.6 Feature Pack 1, 5.6 Common Criteria, 5.6, 5.5, 5.0, and 5.0 Update 3 contains a Local Privilege Esca31Monitor
- CVE-2016-9637The (1) ioport_read and (2) ioport_write functions in Xen, when qemu is used as a device model within Xen, might allow local x86 HVM guest O30Monitor
- CVE-2014-3798The Windows Guest Tools in Citrix XenServer 6.2 SP1 and earlier allows remote attackers to cause a denial of service (guest OS crash) via a 27Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:xen | 4.1.3-2 · Debian:12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- P · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- P
Weakness class (CWE)
CWE-264 · Permissions, Privileges, and Access ControlsCVSS vector
AV:L/AC:L/Au:N/C:N/I:N/A:P
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00001.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00003.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00004.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00005.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00012.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00017.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00018.html
- lists.opensuse.org/opensuse-security-announce/2012-11/msg00017.html
- lists.opensuse.org/opensuse-security-announce/2012-11/msg00018.html
- lists.xen.org/archives/html/xen-announce/2012-09/msg00000.html
- osvdb.org/85197
- secunia.com/advisories/50472
- secunia.com/advisories/50530
- secunia.com/advisories/51413
- secunia.com/advisories/55082
- security.gentoo.org/glsa/glsa-201309-24.xml
- support.citrix.com/article/CTX134708
- wiki.xen.org/wiki/Security_Announcements#XSA-12_hypercall_set_debugreg_vulnerability
- www.debian.org/security/2012/dsa-2544
- www.openwall.com/lists/oss-security/2012/09/05/5
Vendor advisories and official records. Exploit/PoC links are deliberately left out.