CVE-2021-26313: AMD Speculative Code Store Bypass
Noroxi assessment
Priority: Monitor (action score 22/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.32% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: xen (Debian:10) 4.11.4+107-gef32c7afa2-1; xen (Debian:12) 4.14.2+25-gb6a8c4f72d-1.
Low priority for now. Upgrade to xen (Debian:10) 4.11.4+107-gef32c7afa2-1; xen (Debian:12) 4.14.2+25-gb6a8c4f72d-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Potential speculative code store bypass in all supported CPU products, in conjunction with software vulnerabilities relating to speculative execution of overwritten instructions, may cause an incorrect speculation and could result in data leakage.
- Published
- Jun 9, 2021
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 26th percentile
- CWE
- CWE-208
Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| xen | xen | cpe:2.3:o:xen:xen |
| amd | ryzen 5 5600x | cpe:2.3:h:amd:ryzen_5_5600x |
| amd | ryzen 7 2700x | cpe:2.3:h:amd:ryzen_7_2700x |
| amd | ryzen threadripper 2990wx | cpe:2.3:h:amd:ryzen_threadripper_2990wx |
| arm | cortex-a72 | cpe:2.3:h:arm:cortex-a72 |
| broadcom | bcm2711 | cpe:2.3:h:broadcom:bcm2711 |
| intel | core i7-10700k | cpe:2.3:h:intel:core_i7-10700k |
| intel | core i7-7700k | cpe:2.3:h:intel:core_i7-7700k |
| intel | core i9-9900k | cpe:2.3:h:intel:core_i9-9900k |
| intel | xeon silver 4214 | cpe:2.3:h:intel:xeon_silver_4214 |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- arm cortex-a72all versions
- broadcom bcm2711all versions
- debian debian linux10.0
- intel core i7-10700kall versions
- intel core i7-7700kall versions
- intel core i9-9900kall versions
- intel xeon silver 4214all versions
- xen xenall versions
Versions reported by the vendor
Affected version ranges reported by the assigning authority (AMD). Independent of NVD's CPE analysis and usually ahead of it.
AMD All supported processors
- unspecified and later · before undefinedaffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | xen | before 4.11.4+107-gef32c7afa2-1 | 4.11.4+107-gef32c7afa2-1 |
| Debian:12 | xen | before 4.14.2+25-gb6a8c4f72d-1 | 4.14.2+25-gb6a8c4f72d-1 |
Same product
xen: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-10921The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_host_map mapping, whi41Plan
- CVE-2017-10920The grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed by only a GNTMAP_host41Plan
- CVE-2017-10918Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obtain privileged host 41Plan
Published before and after this one in the same product
- ← EarlierCVE-2021-26933Feb 16, 2021 · An issue was discovered in Xen 4.9 through 4.14.x.22Monitor
- ← EarlierCVE-2021-27379Feb 18, 2021 · An issue was discovered in Xen through 4.11.x, allowing x86 Intel HVM guest OS users to achieve unintended read/write DMA access, and possib31Monitor
- Later →CVE-2021-26314Jun 9, 2021 · AMD Speculative execution with Floating-Point Value Injection22Monitor
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 | 4.14.2+25-gb6a8c4f72d-1 · 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.
No history yet (it accumulates with the daily EPSS job).
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
- ArmIntigriti · paid · up to $20,000
- Intel® Vulnerability Disclosure Program Intigriti · disclosure only (VDP)
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-208 · Observable Timing DiscrepancyCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.