CVE-2026-37459Network attack vector

Service interruption via undersized NHC TLV length

Published May 4, 2026 · Updated May 4, 2026

Integer underflow in FRRouting stable/10.0 through stable/10.6 allows remote attackers to interrupt bgpd with a crafted BGP UPDATE message. The bgp_attr_nhc parser checks remaining NHC attribute data against only the advertised TLV value length, then also subtracts the four-byte TLV header. An unauthenticated network-reachable BGP peer can trigger the underflow and interrupt routing service; no data disclosure or modification is reported.

CVSS severity7.5
High
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

Integer underflow in FRRouting stable/10.0 through stable/10.6 allows remote attackers to interrupt bgpd with a crafted BGP UPDATE message. The bgp_attr_nhc parser checks remaining NHC attribute data against only the advertised TLV value length, then also subtracts the four-byte TLV header. An unauthenticated network-reachable BGP peer can trigger the underflow and interrupt routing service; no data disclosure or modification is reported.

The record

CVE
CVE-2026-37459
Published
May 4, 2026
Updated
May 4, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, CWE-191, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 4, 2026CVE publishedPublication date reported by the CVE source.
  2. May 4, 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

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Ubuntu SecurityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Red Hat Product SecurityCVSS: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.

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-400Uncontrolled Resource Consumption
CWE-191Integer Underflow (Wrap or Wraparound)
T1499Endpoint Denial of Service

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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