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Fencer Vulns
critical 9.1

CVE-2026-5720 json

miniupnpd Integer Underflow SOAPAction Header Parsing

published 2026-04-17 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-23565

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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.

Patch / fix

  • miniupnp project miniupnpd 2.3.10
  • miniupnpd Debian 13 2.3.9-2+deb13u1
  • miniupnpd Debian 14 2.3.10-1

debian advisories DEBIAN-CVE-2026-5720

  • miniupnpd Ubuntu Pro 16.04 LTS 1.8.20140523-4.1+deb9u2ubuntu0.1~esm1
  • miniupnpd Ubuntu Pro 18.04 LTS 2.0.20171212-2ubuntu0.1~esm1
  • miniupnpd Ubuntu Pro 20.04 LTS 2.1-6.1ubuntu0.1~esm1
  • miniupnpd Ubuntu Pro 22.04 LTS 2.2.3-1ubuntu0.1~esm1
  • miniupnpd Ubuntu Pro 24.04 LTS 2.3.4-1ubuntu0.1~esm1
  • miniupnpd Ubuntu Pro 26.04 LTS 2.3.9-2ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2026-5720

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • miniupnpd Alpine 3.24 2.3.10-r0

alpine advisories ALPINE-CVE-2026-5720

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-5720 updated cvss 8.2

miniupnpd: miniupnpd: Denial of service or information disclosure due to integer underflow in SOAPAction header parsing.

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

  • miniupnp project miniupnpd

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)
  • CWE-125 Out-of-bounds Read

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.