CVE-2021-26339
MEDIUMCVSS 5.5/10EPSS 0.26%
Last modified
CVE-2021-26339 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A bug in AMD CPU’s core logic may allow for an attacker, using specific code from an unprivileged VM, to trigger a CPU core hang resulting in a potential denial of service. AMD believes the specific code includes a specific x86 instruction sequence that would not be generated by compilers.. EPSS estimates a 0.26% chance of exploitation in the next 30 days.
Description
A bug in AMD CPU’s core logic may allow for an attacker, using specific code from an unprivileged VM, to trigger a CPU core hang resulting in a potential denial of service. AMD believes the specific code includes a specific x86 instruction sequence that would not be generated by compilers.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Amd | Epyc 7763 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7713p Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7713 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7663 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7643 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 75f3 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7543p Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7543 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7513 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7453 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 74f3 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7443p Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7443 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7413 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 73f3 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7343 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7313p Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7313 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 72f3 Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7773x Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7473x Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7573x Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Epyc 7373x Firmware | < milanpi-sp3_1.0.0.7 |
| Amd | Ryzen 7 5700g Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 7 5700ge Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 5 5700g Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 5 5700ge Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 3 5300g Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 3 5300ge Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 7 4700g Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 7 4700ge Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 5 4600g Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 5 4600ge Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 3 4300g Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen 3 4300ge Firmware | < comboam4_v2_pi_1.2.0.6c |
| Amd | Ryzen Threadripper Pro 3945wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 3955wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 3975wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 3995wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 5945wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 5955wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 5965wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 5975wx Firmware | All versions |
| Amd | Ryzen Threadripper Pro 5995wx Firmware | All versions |
| Amd | Ryzen 3 2200u Firmware | All versions |
| Amd | Ryzen 3 2300u Firmware | All versions |
| Amd | Ryzen 3 Pro 2300u Firmware | All versions |
| Amd | Ryzen 5 2500u Firmware | All versions |
| Amd | Ryzen 5 Pro 2500u Firmware | All versions |
| Amd | Ryzen 5 2600h Firmware | All versions |
Showing 50 of 84 affected configurations. See NVD for the full list.
References
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-26339?
A bug in AMD CPU’s core logic may allow for an attacker, using specific code from an unprivileged VM, to trigger a CPU core hang resulting in a potential denial of service. AMD believes the specific code includes a specific x86 instruction sequence that would not be generated by compilers.
How severe is CVE-2021-26339?
CVE-2021-26339 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.
How do I fix CVE-2021-26339?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-26339?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST