CVE-2021-41794Public exploitNetwork attack vector

UPF service interruption via unchecked PFCP length

Published Oct 7, 2021 · Updated Aug 4, 2024

Stack buffer overflow in Open5GS 1.0.0 through 2.3.3 allows remote attackers to interrupt UPF service via crafted PFCP requests. ogs_fqdn_parse treats the first byte of a client-supplied PDI Network Instance as a copy length and passes it to memcpy without validating it against the 100-byte stack destination. Network access to UDP port 8805 is required; a PFCP Association Setup followed by a crafted Session Establishment request corrupts the UPF stack and denies subscriber service.

CVSS severity7.5
High
EPSS probability1.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in Open5GS 1.0.0 through 2.3.3 allows remote attackers to interrupt UPF service via crafted PFCP requests. ogs_fqdn_parse treats the first byte of a client-supplied PDI Network Instance as a copy length and passes it to memcpy without validating it against the 100-byte stack destination. Network access to UDP port 8805 is required; a PFCP Association Setup followed by a crafted Session Establishment request corrupts the UPF stack and denies subscriber service.

The record

CVE
CVE-2021-41794
Published
Oct 7, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.2NCC GroupCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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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