CVE-2026-54909Public exploitNetwork attack vector

Remote client crash via unchecked attribute length

Published Jul 31, 2026 · Updated Jul 31, 2026

Denial of service in Pion STUN before 3.1.5 allows remote attackers to crash clients via a malformed XOR-MAPPED-ADDRESS response. XORMappedAddress.GetFromAs reads the two-byte address-family header before validating the attribute length, so a zero-length value triggers a slice-bounds panic. The attack requires a client to parse a crafted STUN or ICE Binding response; the panic interrupts that consuming process without affecting confidentiality or integrity.

CVSS severity5.3
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Pion STUN before 3.1.5 allows remote attackers to crash clients via a malformed XOR-MAPPED-ADDRESS response. XORMappedAddress.GetFromAs reads the two-byte address-family header before validating the attribute length, so a zero-length value triggers a slice-bounds panic. The attack requires a client to parse a crafted STUN or ICE Binding response; the panic interrupts that consuming process without affecting confidentiality or integrity.

The record

CVE
CVE-2026-54909
Published
Jul 31, 2026
Updated
Jul 31, 2026
Vendor
Pion
Product
STUN
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Pion · STUNversion=< 3.1.3

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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