CVE-2026-10657: Zephyr's DNS resolver detects mDNS (.local) queries in dns_resolve_name_internal() (subsys/net/lib/dns/resolve

Q: How do I fix CVE-2026-10657?

zephyr: upgrade to newer than 4.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-10657 being exploited?

CVE-2026-10657 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-10657 affect?

CVE-2026-10657 affects zephyr. Severity is low (CVSS 3.7). Zephyr's DNS resolver detects mDNS (.local) queries in dns_resolve_name_internal() (subsys/net/lib/dns/resolve.c) with memcmp(strrchr(query, '.'), ".local", 7), which always reads a fixed 7 bytes from the suffix pointer. When the resolved h

Q: How urgent is CVE-2026-10657?

Priority 32/100. Public exploit reference; Remotely exploitable, no login, no user action

This week

LOW 3.7REMOTEUPGRADE

CVE-2026-10657 is a low-severity flaw (CVSS 3.7) affecting zephyr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Zephyr's DNS resolver detects mDNS (.local) queries in dns_resolve_name_internal() (subsys/net/lib/dns/resolve.c) with memcmp(strrchr(query, '.'), ".local", 7), which always reads a fixed 7 bytes from the suffix pointer. When the resolved hostname's final label is shorter than 7 bytes (e.g. names ending in .org, .com, .net, .io, or a trailing dot), the comparison reads 1-2 bytes past the string's NUL terminator. The hostname (query) is the calle

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	3.7 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-07-05
Last modified	2026-10-25

Publisher (CNA): Zephyr Project · Vendor: zephyrproject

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-05 23:16 UTCPublished CVE record published
2026-10-25 15:10 UTCUpdated Record last modified

zephyrproject zephyr UPGRADE

Affected: >= 1.10.0 and <= 4.4.0

Fixed in: newer than 4.4.0

Safe to downgrade to: a release before 1.10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-10657?

zephyr: upgrade to newer than 4.4.0. Exact commands for each OS are on this page.

Is CVE-2026-10657 being exploited?

CVE-2026-10657 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-10657 affect?

CVE-2026-10657 affects zephyr. Severity is low (CVSS 3.7). Zephyr's DNS resolver detects mDNS (.local) queries in dns_resolve_name_internal() (subsys/net/lib/dns/resolve.c) with memcmp(strrchr(query, '.'), ".local", 7), which always reads a fixed 7 bytes from the suffix pointer. When the resolved h

How urgent is CVE-2026-10657?

Priority 32/100. Public exploit reference; Remotely exploitable, no login, no user action

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References

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