Memory corruption via Proxy Protocol out-of-bounds write
Published Sep 19, 2026 · Updated Sep 19, 2026
Out-of-bounds write in Exim 4.83 through 4.100.0 allows remote attackers to corrupt memory via Proxy Protocol traffic. The public advisory does not identify the affected function, buffer, or malformed field that causes the write beyond the buffer boundary. Exploitation requires Proxy Protocol use with an attacker-controlled proxy; published impacts include data corruption, limited disclosure, and service interruption.
Summary
What happened
Out-of-bounds write in Exim 4.83 through 4.100.0 allows remote attackers to corrupt memory via Proxy Protocol traffic. The public advisory does not identify the affected function, buffer, or malformed field that causes the write beyond the buffer boundary. Exploitation requires Proxy Protocol use with an attacker-controlled proxy; published impacts include data corruption, limited disclosure, and service interruption.
The record
- CVE
- CVE-2026-94054
- Published
- Sep 19, 2026
- Updated
- Sep 19, 2026
- Vendor
- LibSPF2 Project
- Product
- Exim
- Classifications
- CWE-787, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 19, 2026CVE publishedPublication date reported by the CVE source.
- Sep 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=4.83 <4.100.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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