CVE Intelligence
Medium

CVE-2026-34019 — BIG-IP BFD vulnerability

When Bidirectional Forwarding Detection (BFD) is configured in Static and Dynamic routing protocols, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to stop processing BFD packets and cause the configured routing protocol to fail over.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Published May 13, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: f5

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+5
  • Technical severity (medium)+3
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.4%
ahead of 33% of scored CVEs · Oct 14, 2026
Affects
F5
BIG-IP and 21 more
CVSS base
5.3
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (F5 BIG-IP, F5 Big-ip Access Policy Manager, F5 Big-ip Advanced Firewall Manager…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
F5 BIG-IP ≥ 16.1.0≥ 17.1.0 and < 17.1.3≥ 17.5.0 and < 17.5.1 Vulnerable CVE Program (cve.org) e CISA ADP
F5 Big-ip Access Policy Manager version 17.5.0≥ 16.1.0 and ≤ 16.1.6≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Advanced Firewall Manager ≥ 17.1.0 and ≤ 17.1.2version 17.5.0≥ 16.1.0 and ≤ 16.1.6 Vulnerable NIST National Vulnerability Database
F5 Big-ip Advanced Web Application Firewall ≥ 17.1.0 and ≤ 17.1.2version 17.5.0≥ 16.1.0 and ≤ 16.1.6 Vulnerable NIST National Vulnerability Database
F5 Big-ip Analytics ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Application Acceleration Manager ≥ 17.1.0 and ≤ 17.1.2version 17.5.0≥ 16.1.0 and ≤ 16.1.6 Vulnerable NIST National Vulnerability Database
F5 Big-ip Application Security Manager ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Application Visibility And Reporting ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Automation Toolchain version 17.5.0≥ 16.1.0 and ≤ 16.1.6≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Carrier-grade Nat ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Container Ingress Services ≥ 16.1.0 and ≤ 16.1.6≥ 17.1.0 and ≤ 17.1.2version 17.5.0 Vulnerable NIST National Vulnerability Database
F5 Big-ip Ddos Hybrid Defender ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Domain Name System ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Edge Gateway ≥ 17.1.0 and ≤ 17.1.2version 17.5.0≥ 16.1.0 and ≤ 16.1.6 Vulnerable NIST National Vulnerability Database
F5 Big-ip Fraud Protection Service ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Global Traffic Manager ≥ 17.1.0 and ≤ 17.1.2version 17.5.0≥ 16.1.0 and ≤ 16.1.6 Vulnerable NIST National Vulnerability Database
F5 Big-ip Link Controller ≥ 17.1.0 and ≤ 17.1.2version 17.5.0≥ 16.1.0 and ≤ 16.1.6 Vulnerable NIST National Vulnerability Database
F5 Big-ip Local Traffic Manager ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Policy Enforcement Manager ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Ssl Orchestrator version 17.5.0≥ 16.1.0 and ≤ 16.1.6≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Webaccelerator ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database
F5 Big-ip Websafe ≥ 16.1.0 and ≤ 16.1.6version 17.5.0≥ 17.1.0 and ≤ 17.1.2 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.3 CVSS 4.0 Medium — — f5sirt@f5.com via NIST National Vulnerability Database
6.3 CVSS 4.0 Medium — — f5 via CVE Program (cve.org) e CISA ADP
5.3 CVSS 3.1 Medium 3.9 1.4 f5sirt@f5.com via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium — — f5 via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L (score shown at the top: f5sirt@f5.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-410

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.40%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · f5/big-ip
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 5.3
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    May 13, 2026 · f5

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

Elsewhere on this site

F5
every CVE for this vendor
CWE-410
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-94127 F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability KEV 23d
  • CVE-2026-42937 iControl REST and tmsh vulnerability May 13, 2026
  • CVE-2026-42919 F5 BIG-IP Appliance Mode Vulnerability May 13, 2026
  • CVE-2026-42920 BIG-IP DTLS Vulnerability May 13, 2026
  • CVE-2026-42924 BIG-IP iControl SOAP vulnerability May 13, 2026
  • CVE-2026-42930 Appliance mode iControl REST vulnerability May 13, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-34019 is "BIG-IP BFD vulnerability", rated Medium. It affects BIG-IP (F5); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.3 describes technical severity. EPSS 0.40% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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