How severe is CVE-2026-5720?

CVE-2026-5720 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2026-5720 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5720?

CVE-2026-5720 affects Miniupnp Project Miniupnpd. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5720?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-5720 have an EU (EUVD) identifier?

Yes. CVE-2026-5720 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23565.

When was CVE-2026-5720 published?

CVE-2026-5720 was published on 2026-04-17 and last updated on 2026-06-29.

CVE-2026-5720

CVE-2026-5720 is a critical-severity vulnerability in Miniupnp Project Miniupnpd with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 7.1
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23565
Weakness: CWE-125
Affected product: Miniupnp Project Miniupnpd
Published: 2026-04-17
Last modified: 2026-06-29

Description

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 to scan memory far beyond the allocated HTTP request buffer.

Frequently asked questions

What is CVE-2026-5720?: 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 to scan memory far beyond the allocated HTTP request buffer.
How severe is CVE-2026-5720?: CVE-2026-5720 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2026-5720 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5720?: CVE-2026-5720 affects Miniupnp Project Miniupnpd. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5720?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-5720 have an EU (EUVD) identifier?: Yes. CVE-2026-5720 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23565.
When was CVE-2026-5720 published?: CVE-2026-5720 was published on 2026-04-17 and last updated on 2026-06-29.

References

Affected products (1)

cpe:2.3:a:miniupnp_project:miniupnpd:*:*:*:*:*:*:*:*

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