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NVD / CVE Program· CNA fedora

CVE-2026-3842: Qemu-kvm: hyperv/syndbg: missing mapped-length guard after cpu_physical_memory_map causes host oob write

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.16% (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: gitlab.com/qemu-project/qemu qemu 11.0.0; azl3 qemu 9.1.0-10 on Azure Linux 3.0 9.1.0-11.

Low priority for now. Upgrade to gitlab.com/qemu-project/qemu qemu 11.0.0; azl3 qemu 9.1.0-10 on Azure Linux 3.0 9.1.0-11 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

A flaw was found in QEMU. This vulnerability allows a local attacker within a guest virtual machine to write data beyond its allocated memory. This occurs when cpu_physical_memory_map() returns a shorter length than expected, leading to an out-of-bounds write. Successful exploitation could result in unauthorized access to guest memory or corruption of heap-allocated objects, potentially causing information disclosure, data integrity issues, or a denial of service.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 15, 2026
Updated
Sep 1, 2026
EPSS
0.1% · 6th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · fedora
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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.

Follow CVE-2026-3842

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
enterprise linux10
enterprise linux6
enterprise linux7
enterprise linux8
enterprise linux9
openshift4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (fedora). Independent of NVD's CPE analysis and usually ahead of it.

  • gitlab.com/qemu-project/qemu qemu

    • 7.1.0 and later · before 11.0.0affected · semver

  • Red Hat Red Hat Enterprise Linux 10

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 6

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 7

    • all versionsunknown
    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 8

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 9

    • all versionsunknown

  • Red Hat Red Hat OpenShift Container Platform 4

    • all versionsunknown

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12qemufrom 0—
Debian:13qemubefore 1:10.0.10+ds-0+deb13u11:10.0.10+ds-0+deb13u1
Debian:14qemubefore 1:10.2.2+ds-11:10.2.2+ds-1
SUSE:Linux Enterprise Micro 5.5qemubefore 7.1.0-150500.49.42.17.1.0-150500.49.42.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7qemubefore 9.2.4-150700.3.20.19.2.4-150700.3.20.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7qemu-linux-userbefore 9.2.4-150700.3.20.19.2.4-150700.3.20.1
SUSE:Linux Enterprise Server 15 SP6-LTSSqemubefore 8.2.10-150600.3.49.18.2.10-150600.3.49.1

Same product

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Other highest-scoring records for the same primary product.

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  • CVE-2026-76578Ipa: freeipa: freeipa: unauthenticated ldap client can obtain administrator credentials via the self-managed-token aci
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-15714Jul 14, 2026 · Libsoup: soupmultipartinputstream: libsoup: out-of-bounds read in soup_multipart_input_stream_read_headers via an oversized multipart boundary string
    26Monitor
  • ← EarlierCVE-2026-15779Jul 15, 2026 · Samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation
    24Monitor
  • Later →CVE-2026-5674Jul 16, 2026 · Pipewire: pipewire: sandbox escape and arbitrary code execution via malicious library loading
    35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
gitlab.com/qemu-project/qemu qemu11.0.0Vendor (CNA)
azl3 qemu 9.1.0-10 on Azure Linux 3.09.1.0-11 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:qemu1:10.0.10+ds-0+deb13u1 · Debian:13Package registry (OSV)
suse:qemu9.2.4-150700.3.20.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:qemu-linux-user9.2.4-150700.3.20.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package 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.

EPSS, last 120 days

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.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-119777107 days apartGstreamer1-plugins-bad-free: gstreamer1-plugins-bad-free: stack buffer overflow in h.266/vvc parser
    35Monitor
  • CVE-2026-8647691 days apartGstreamer1-plugins-base: gst-plugins-base: heap buffer overflow via unvalidated gstvideometa plane extents in gst_video_frame_map_id and video_meta_deserialize
    33Monitor
  • CVE-2026-8162765 days apartQemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smram
    32Monitor
  • CVE-2026-1822014 days apartBinutils: binutils: out-of-bounds write in bfd dlx elf backend relocation processing
    31Monitor
  • CVE-2026-9718571 days apartGimp: gimp: out-of-bounds write in gimpressionist plugin via crafted preset file
    31Monitor
  • CVE-2026-10125883 days apartGhostscript: ghostscript: -dsafer sandbox bypass via type 5 shading oob write and procedure-stream use-after-free
    31Monitor

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

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

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
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records