7.8

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

Awaiting analysis
AliasesUBUNTU-CVE-2026-3842DEBIAN-CVE-2026-3842
Published 16-07-2026Last modified 01-09-2026

Vulnerability summary

CVE-2026-3842 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in qemu. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.17%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 4
SUSE-SU-2026:2385-1SUSE-SU-2026:2386-1SUSE-SU-2026:2388-1USN-8161-1

Timeline

  1. 16-07-2026
    PublishedVulnerability first disclosed.
  2. 01-09-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.17% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu2 products
  • qemuAll versions (No fix recorded) | < 1:8.2.2+ds-0ubuntu1.16 | < 1:10.1.0+ds-5ubuntu2.6
  • qemu-hweAll versions (No fix recorded)
Debian1 product
  • qemuAll versions (No fix recorded) | < 1:10.0.10+ds-0+deb13u1 | < 1:10.2.2+ds-1

2 vendors · 3 products

References

8 links