CVE-2026-40669
An off-by-one error in AMD Secure Encrypted Virtualization (SEV) firmware could allow an attacker with hypervisor access to corrupt the…
A 0-10 score for how bad the bug is in the worst case. It does not say how common the affected setup is.What do these mean? →4.0MediumCNA
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 9/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
AMD Secure Encrypted Virtualization (SEV) firmware is affected by an off-by-one error that lets a local attacker with hypervisor access corrupt the Reverse Map Table, which can compromise the integrity of guest memory. Exploiting it requires high-privilege login on the local system, and no user action is needed.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
An off-by-one error in AMD Secure Encrypted Virtualization (SEV) firmware could allow an attacker with hypervisor access to corrupt the Reverse Map Table (RMP) table, potentially resulting in loss of guest memory integrity.
cve.now Index
9Pcve.now Index 9 of 100 · methodology v3 · provisional
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity4/10CVSS 4.0
- No patch5/5No patch listed yet
What would change the score
- Would score about 64 if added to CISA KEV
- Would score about 59 if CISA's SSVC rates exploitation active
- Would score about 31 if advisories confirm default setups are exposed
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-40669 (An off-by-one error in AMD Secure Encrypted Virtualization (SEV) firmware could allow an attacker with hypervisor access to corrupt the…), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-40669 (entry last updated 2026-11-10): Affected: - AMD AMD EPYC™ 9004 Series Processors: version range not reported - AMD AMD EPYC™ 7003 Series Processors: version range not reported - AMD AMD EPYC™ 8004 Series Processors: version range not reported - AMD AMD EPYC™ Embedded 7003 Series Processors: version range not reported - AMD AMD EPYC™ Embedded 9004 Series Processors (formerly codenamed "Genoa"): version range not reported - AMD AMD EPYC™ Embedded 9004 Series Processors (formerly codenamed "Bergamo"): version range not reported - AMD AMD EPYC™ Embedded 8004 Series Processors: version range not reported Fixed versions: none listed yet. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-40669 is not listed as of cve.now's last read. This KEV status is for CVE-2026-40669 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-3038.html Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-40669 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-40669.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- AMD AMD EPYC™ 9004 Series Processors
Version range not reported
- AMD AMD EPYC™ 7003 Series Processors
Version range not reported
- AMD AMD EPYC™ 8004 Series Processors
Version range not reported
- AMD AMD EPYC™ Embedded 7003 Series Processors
Version range not reported
- AMD AMD EPYC™ Embedded 9004 Series Processors (formerly codenamed "Genoa")
Version range not reported
- AMD AMD EPYC™ Embedded 9004 Series Processors (formerly codenamed "Bergamo")
Version range not reported
- AMD AMD EPYC™ Embedded 8004 Series Processors
Version range not reported
Evidence 3
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Link
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.