How severe is CVE-2026-54909?

CVE-2026-54909 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-54909?

CVE-2026-54909 affects the following packages: github.com/pion/stun/v3 (Go), github.com/pion/stun/v2 (Go), github.com/pion/stun (Go). Ecosystems affected: Go.

How do I fix CVE-2026-54909?

Update github.com/pion/stun/v3 to 3.1.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54909 is resolved across your whole dependency graph.

How do I detect CVE-2026-54909 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/pion/stun/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-54909 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-54909 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54909 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-54909?

CVE-2026-54909 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 51th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-54909?

CVE-2026-54909 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-54909 published, and has it been updated?

CVE-2026-54909 was published on July 31, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-54909 — stun

MEDIUMFix: pion/stun@fa9f074

CVE-2026-54909 is a medium-severity (CVSS 5.3) Improper Input Validation vulnerability in github.com/pion/stun/v3. A fix is available for github.com/pion/stun/v3 — see the affected versions and patch details below.

Pion STUN vulnerable to remote denial of service via panic while parsing a malformed XOR-MAPPED-ADDRESS attribute

Also known asGHSA-34rh-wp3j-6cxcGO-2026-6163

Published

Jul 31, 2026

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

1 / 3

Exploits

None indexed

Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-54909.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs51th percentile — riskier than 51% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-54909 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 397,508 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

3 pkgs affected

🐹github.com/pion/stun/v3🐹github.com/pion/stun/v2🐹github.com/pion/stun

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Remote denial of service via panic while parsing a malformed XOR-MAPPED-ADDRESS attribute

Patches

Upgrade to v3.1.5 or later. This version includes this patch https://github.com/pion/stun/pull/278 which fixes the issue.

Workarounds

No work around; please upgrade to v3.1.5 or a newer version.

Affected Packages

3 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/pion/stun/v3`	all versions	3.1.5`go get github.com/pion/stun/v3@v3.1.5`
🐹Go	`github.com/pion/stun/v2`	all versions	No fix
🐹Go	`github.com/pion/stun`	all versions	No fix

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/pion/stun/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/pion/stun/v3 to 3.1.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54909 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact Remote denial of service via panic while parsing a malformed XOR-MAPPED-ADDRESS attribute ### Patches Upgrade to v3.1.5 or later. This version includes this patch https://github.com/pion/stun/pull/278 which fixes the issue. ### Workarounds No work around; please upgrade to v3.1.5 or a newer version.