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CVE Record

CVE-2026-37459: An integer underflow in FRRouting (FRR) stable/10.0 to stable/10.6 allows attackers to cause a Denial of Se...

An integer underflow in FRRouting (FRR) stable/10.0 to stable/10.6 allows attackers to cause a Denial of Service (DoS) via supplying a crafted BGP UPDATE message.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

FRRouting can be crashed by a specially formed BGP update. The issue affects FRR stable/10.0 through stable/10.6 according to the CVE description. The business impact is routing service disruption, not data theft. No source in the bundle states active exploitation.

Executive priority

Prioritize patching on production routing infrastructure and exposed BGP peers. The main risk is network availability loss, which can affect customer connectivity and internal routing stability. No evidence provided indicates data compromise or confirmed exploitation.

Technical view

CVE-2026-37459 is an integer underflow in FRRouting BGP UPDATE handling that can trigger denial of service. CVSS 3.1 is 7.5: network reachable, low complexity, no privileges or user interaction, with high availability impact only. CWE mappings are CWE-191 and CWE-400.

Likely exposure

Exposure is most likely on systems running FRRouting with BGP enabled, especially routers or route servers accepting BGP UPDATE messages from peers. The bundle does not identify specific distributions beyond Red Hat advisories and upstream FRR stable/10.0 to stable/10.6.

Exploitation context

The vulnerability is remotely reachable over BGP in affected FRR deployments, but the provided sources do not show public exploit use, KEV listing, or weaponized details. Treat internet-facing or broadly peered BGP services as higher operational risk.

Researcher notes

The bundle names an upstream FRR commit and Red Hat advisories, but does not provide fixed version details or affected CPEs. Analysis should stay focused on BGP UPDATE parsing paths and availability impact. Avoid assuming exploit maturity beyond the CVE description.

Mitigation direction

  • Apply relevant FRRouting or operating-system vendor updates as they become available.
  • Review Red Hat advisories RHSA-2026:24347 and RHSA-2026:24370 if using Red Hat packages.
  • Restrict BGP peering to trusted, expected neighbors wherever operationally possible.
  • Use routing policy and control-plane protections to reduce untrusted BGP message exposure.
  • Monitor FRR/BGP daemon restarts until patched.

Validation and detection

  • Inventory systems running FRRouting and record package or branch versions.
  • Identify FRR deployments with BGP enabled and active peers.
  • Prioritize versions matching stable/10.0 through stable/10.6.
  • Confirm applicable vendor advisory packages are installed.
  • Review logs for unexpected BGP daemon crashes or restarts.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-191: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cwe · low confidence lookup

CWE-400: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-37459 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6CISA-ADP
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-37459Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPfrr: denial of service via crafted BGP UPDATE message
other:Red Hat severity ratingcvssV3_1
  • 2026-05-04T19:02:45.777Z: Reported to Red Hat.
  • 2026-05-04T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-191CWE-400

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.