Debian LinuxOperating system · Debian
CVE-2021-26313
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedPotential 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceAMD CPU vulnerability allowing speculative code store bypass where overwritten instructions may be speculatively executed, potentially causing incorrect branch prediction and data leakage through speculative execution side channels.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Debian LinuxOperating system
= 10.0all versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify CPU vendor and modelRun 'lscpu' or 'cat /proc/cpuinfo' to determine the CPU vendor (AMD, Intel, Arm) and exact model numberAffected if The CPU is from the affected product list (AMD processors, listed Intel models, Arm Cortex A72, or Broadcom Bcm2711)
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Check Linux kernel microcode versionOn Linux, check /sys/devices/system/cpu/cpu0/microcode/version or run 'dmesg | grep microcode' after boot to see loaded microcode versionAffected if Microcode version is older than the fixed version provided by AMD or Intel firmware updates for this CVE
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Verify CPU feature flags for speculation mitigationsRun 'lscpu' and examine flags or check /proc/cpuinfo for speculation-related flags (such as spec_ctrl, ibpb, retpoline)Affected if Speculation control features (IBPB, STIBP, SPEC_CTRL) are absent or disabled, indicating the mitigation is not active
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Check BIOS/firmware versionFor servers/workstations, use vendor-specific tools (like dmidecode on Linux or BIOS setup) to check the BIOS/firmware versionAffected if The BIOS/firmware version predates the vendor patch release date for this CVE
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For Xen hypervisors, check hypervisor versionRun 'xl info' or 'xm info' to display Xen version and microcode level; check 'xl dmesg' for loaded microcode informationAffected if Running an unpatched Xen version without updated hypervisor microcode
A system is affected if it runs on the listed hardware (AMD CPU, specific Intel models, Arm Cortex A72, or Broadcom Bcm2711) and lacks the corresponding firmware/microcode updates that address this speculative execution vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply AMD microcode/firmware updates and BIOS updates from system vendors; software mitigations (compiler flags, task scheduling) may provide partial protection but hardware updates are required for complete remediation.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,352.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26313 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-26313 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data