CVE-2026-5720: miniupnpd contains an integer underflow vulnerability in SOAPAction header parsing that allows remote attacker

Q: How do I fix CVE-2026-5720?

miniupnpd: upgrade to 2.3.10. Exact commands for each OS are on this page.

Q: Is CVE-2026-5720 being exploited?

CVE-2026-5720 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-2026-5720 affect?

CVE-2026-5720 affects miniupnpd. Severity is critical (CVSS 9.1). miniupnpd contains an integer underflow vulnerability in SOAPAction header parsing that allows remote attackers to cause a denial of service or information disclosure by sending a malformed SOAPAction header with a single quote. Attackers c

Q: How urgent is CVE-2026-5720?

Priority 50/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-5720 is a critical-severity flaw (CVSS 9.1) affecting miniupnpd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

miniupnpd contains an integer underflow vulnerability in SOAPAction header parsing that allows remote attackers to cause a denial of service or information disclosure by sending a malformed SOAPAction header with a single quote. Attackers can trigger an out-of-bounds memory read by exploiting improper length validation in ParseHttpHeaders(), where the parsed length underflows to a large unsigned value when passed to memchr(), causing the process

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-125, CWE-191
Published	2026-04-17
Last modified	2026-10-26

Publisher (CNA): VulnCheck · Vendor: miniupnp project

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-17 22:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

miniupnp project miniupnpd UPGRADE

Affected: < 2.3.10

Fixed in: 2.3.10

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy miniupnpd || rpm -q miniupnpd || miniupnpd --version

2. UPGRADE to 2.3.10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade miniupnpd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade miniupnpd

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2026-5720?

miniupnpd: upgrade to 2.3.10. Exact commands for each OS are on this page.

Is CVE-2026-5720 being exploited?

CVE-2026-5720 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-2026-5720 affect?

CVE-2026-5720 affects miniupnpd. Severity is critical (CVSS 9.1). miniupnpd contains an integer underflow vulnerability in SOAPAction header parsing that allows remote attackers to cause a denial of service or information disclosure by sending a malformed SOAPAction header with a single quote. Attackers c

How urgent is CVE-2026-5720?

Priority 50/100. Critical severity; Remotely exploitable, no login, no user action

References

← Back to latest CVEs