CVE-2026-48691Network attack vector

Heap memory corruption via AS_PATH length truncation

Published May 26, 2026 · Updated May 26, 2026

Heap buffer overflow in FastNetMon Community Edition before 1.2.9 allows remote attackers to corrupt memory via a long BGP AS_PATH. IPv4UnicastAnnounce::get_attributes() narrows the computed attribute length to uint8_t, sizes a heap buffer from the truncated value, then appends every four-byte ASN. An AS_PATH with at least 64 ASNs reaches the overwrite through BGP route forwarding or unauthenticated gRPC ExecuteBan; the gRPC listener is loopback-only by default.

CVSS severity9.8
Critical
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in FastNetMon Community Edition before 1.2.9 allows remote attackers to corrupt memory via a long BGP AS_PATH. IPv4UnicastAnnounce::get_attributes() narrows the computed attribute length to uint8_t, sizes a heap buffer from the truncated value, then appends every four-byte ASN. An AS_PATH with at least 64 ASNs reaches the overwrite through BGP route forwarding or unauthenticated gRPC ExecuteBan; the gRPC listener is loopback-only by default.

The record

CVE
CVE-2026-48691
Published
May 26, 2026
Updated
May 26, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, CWE-122, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2026CVE publishedPublication date reported by the CVE source.
  2. May 26, 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?

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

7.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
CWE-122Heap-based Buffer Overflow
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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