CVE-2026-55490: OpenWrt is a Linux operating system targeting embedded devices

Q: How do I fix CVE-2026-55490?

openwrt: upgrade to 25.12.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-55490 being exploited?

CVE-2026-55490 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-2026-55490 affect?

CVE-2026-55490 affects openwrt. Severity is medium (CVSS 6.5). OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending

Q: How urgent is CVE-2026-55490?

Priority 46/100. Public exploit reference; On your watchlist

This month

MEDIUM 6.5WATCHLISTUPGRADE

CVE-2026-55490 is a medium-severity flaw (CVSS 6.5) affecting openwrt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending a single crafted UDP packet. The message length underflows before a bounds check and is then passed to memcpy as a very large size. This issue is fixed v25.12.5.

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-191
Published	2026-07-07
Last modified	2026-07-10

Publisher (CNA): GitHub, Inc. · Vendor: openwrt

Last updated 2026-07-10 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-07 22:16 UTCPublished CVE record published
2026-07-10 17:37 UTCUpdated Record last modified

openwrt openwrt UPGRADE

Affected: < 25.12.5

Fixed in: 25.12.5

Safe to downgrade to: no unaffected older release

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-2026-55490?

openwrt: upgrade to 25.12.5. Exact commands for each OS are on this page.

Is CVE-2026-55490 being exploited?

CVE-2026-55490 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-2026-55490 affect?

CVE-2026-55490 affects openwrt. Severity is medium (CVSS 6.5). OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending

How urgent is CVE-2026-55490?

Priority 46/100. Public exploit reference; On your watchlist

Software pages

OpenWrt vulnerabilities

Related CVEs

CVE-2026-62948 CRITICAL 9.6 UPGRADE OpenWrt is a Linux operating system targeting embedded devices
CVE-2026-62947 MEDIUM 4.9 UPGRADE OpenWrt is a Linux operating system targeting embedded devices

References

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