CVE-2026-8836: A vulnerability was found in lwIP up to 2.2.1

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CRITICAL 9.8REMOTE

CVE-2026-8836 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability was found in lwIP up to 2.2.1. Affected is the function snmp_parse_inbound_frame of the file src/apps/snmp/snmp_msg.c of the component snmpv3 USM Handler. Performing a manipulation of the argument msgAuthenticationParameters results in stack-based buffer overflow. The attack may be initiated remotely. The patch is named 0c957ec03054eb6c8205e9c9d1d05d90ada3898c. It is suggested to install a patch to address this issue. Two separate

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-119, CWE-121
Published	2026-05-18
Last modified	2026-08-22

Publisher (CNA): VulDB

Last updated 2026-08-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-05-18 19:16 UTCPublished CVE record published
2026-08-22 09:16 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · proftpd · FIXED · 1.3.9e-1.fc46 · FEDORA-2026-fc0d87d66e · source

sudo dnf upgrade --advisory=FEDORA-2026-fc0d87d66e

Ubuntu 20.04 · lwip · FIXED · 2.1.2+dfsg1-4ubuntu0.1~esm1

sudo apt update && sudo apt install --only-upgrade lwip dpkg --compare-versions "$(dpkg-query -W -f='${Version}' lwip)" ge "2.1.2+dfsg1-4ubuntu0.1~esm1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · lwip · FIXED · 2.1.3+dfsg1-1ubuntu0.1~esm1

sudo apt update && sudo apt install --only-upgrade lwip dpkg --compare-versions "$(dpkg-query -W -f='${Version}' lwip)" ge "2.1.3+dfsg1-1ubuntu0.1~esm1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · lwip · FIXED · 2.2.0+dfsg1-6.1ubuntu0.1~esm1

sudo apt update && sudo apt install --only-upgrade lwip dpkg --compare-versions "$(dpkg-query -W -f='${Version}' lwip)" ge "2.2.0+dfsg1-6.1ubuntu0.1~esm1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · lwip · NO FIX YET

Debian 13 · lwip · FIXED · 2.2.1+dfsg1-1+deb13u1

sudo apt update && sudo apt install --only-upgrade lwip dpkg --compare-versions "$(dpkg-query -W -f='${Version}' lwip)" ge "2.2.1+dfsg1-1+deb13u1" && echo PATCHED || echo STILL-VULNERABLE

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: Hunt-Benito/lwip-snmpv3-stack-overflow-cve-2026-8836-critical-embedded-rce (0 stars)

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-2026-8836?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-8836 being exploited?

CVE-2026-8836 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-2026-8836 affect?

CVE-2026-8836 affects affected software. Severity is critical (CVSS 9.8). A vulnerability was found in lwIP up to 2.2.1. Affected is the function snmp_parse_inbound_frame of the file src/apps/snmp/snmp_msg.c of the component snmpv3 USM Handler. Performing a manipulation of the argument msgAuthenticationParameters

How urgent is CVE-2026-8836?

Priority 59/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

References

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