The physdev_get_free_pirq hypercall in arch/x86/physdev.c in Xen 4.1.x and Citrix XenServer 6.0.2 and earlier uses the return value of the g
The physdev_get_free_pirq hypercall in arch/x86/physdev.c in Xen 4.1.x and Citrix XenServer 6.0.2 and earlier uses the return value of the get_free_pirq function as an array index without checking that the return value indicates an error, which allows guest OS users to cause a denial of service (invalid memory write and host crash) and possibly gain privileges via unspecified vectors.
- Published
- Nov 23, 2012
- Updated
- Jun 16, 2026
- EPSS
- 0.4% · 36th percentile
- CWE
- CWE-20
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Report tools
Action score
24
Monitor
Low priority for now.
- CVSS
- 24 / 40 · 6.1 / 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
- citrix xenserver5.0
- citrix xenserver5.5
- citrix xenserver5.6
- citrix xenserver6.0
- xen xen4.1.0
- xen xen4.1.1
- xen xen4.1.2
- xen xen4.1.3
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 |
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.
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
- P · data can be read
- Integrity
- P · data or configuration can be modified
- Availability
- C · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- P
- Integrity impact
- P
- Availability impact
- C
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
AV:L/AC:L/Au:N/C:P/I:P/A:C
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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
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/msg00003.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00004.html
- lists.opensuse.org/opensuse-security-announce/2012-09/msg00017.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/msg00001.html
- 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-13_hypercall_physdev_get_free_pirq_vulnerability
- www.openwall.com/lists/oss-security/2012/09/05/6
- www.securityfocus.com/bid/55406
- www.securitytracker.com/id?1027480
- xenbits.xen.org/hg/xen-4.1-testing.hg/rev/6779ddca8593
- security.gentoo.org/glsa/201604-03
Vendor advisories and official records. Exploit/PoC links are deliberately left out.