Packet forgery via skipped MAC verification
Published Aug 19, 2026 · Updated Aug 19, 2026
Authentication bypass in FreeBSD wg(4) allows remote attackers to inject or alter WireGuard tunnel packets via forged or modified traffic. In the wg(4) receive path, the driver submits ChaCha20-Poly1305 decryption to the OpenCrypto Framework and then accepts the returned packet without checking whether Poly1305 tag verification succeeded. Reachability is limited to systems using wg(4) on 14.4-RELEASE before p8, 15.0-RELEASE before p12, or 15.1-RELEASE before p2, and exploitation requires either replay-window guessing for blind UDP injection or interception of in-flight packets.
Summary
What happened
Authentication bypass in FreeBSD wg(4) allows remote attackers to inject or alter WireGuard tunnel packets via forged or modified traffic. In the wg(4) receive path, the driver submits ChaCha20-Poly1305 decryption to the OpenCrypto Framework and then accepts the returned packet without checking whether Poly1305 tag verification succeeded. Reachability is limited to systems using wg(4) on 14.4-RELEASE before p8, 15.0-RELEASE before p12, or 15.1-RELEASE before p2, and exploitation requires either replay-window guessing for blind UDP injection or interception of in-flight packets.
The record
- CVE
- CVE-2026-58085
- Published
- Aug 19, 2026
- Updated
- Aug 19, 2026
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- CWE-347, T1565.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 19, 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=14.4-RELEASE <p8
- Affected versionversion=15.0-RELEASE <p12
- Affected versionversion=15.1-RELEASE <p2
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
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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