Memory corruption via L2TP hostname off-by-one write
Published Sep 7, 2026 · Updated Sep 9, 2026
An off-by-one write in the D-Link DIR-605 B1v202WWB03 L2TP parser allows remote attackers to corrupt device memory. The tunnel_set_params function in progs.gpl/pppd.alpha/l2tp/tunnel.c mishandles a crafted peer_hostname AVP and writes beyond its intended buffer. No authentication or user interaction is required, but exploitation is highly complex; the public proof of concept establishes memory corruption, not reliable code execution.
Summary
What happened
An off-by-one write in the D-Link DIR-605 B1v202WWB03 L2TP parser allows remote attackers to corrupt device memory. The tunnel_set_params function in progs.gpl/pppd.alpha/l2tp/tunnel.c mishandles a crafted peer_hostname AVP and writes beyond its intended buffer. No authentication or user interaction is required, but exploitation is highly complex; the public proof of concept establishes memory corruption, not reliable code execution.
The record
- CVE
- CVE-2026-86297
- Published
- Sep 7, 2026
- Updated
- Sep 9, 2026
- Vendor
- D-Link
- Product
- DIR-605
- Classifications
- CWE-189, CWE-193, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 7, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=B1v202WWB03
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
- D-Link DIR-605 L2TP Host Name AVP Out-of-Bounds Write proof of conceptproof of concept · unverified
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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