Memory disclosure via stale HTTP header pointers
Published Jun 17, 2024 · Updated Sep 15, 2025
Use-after-free in lighttpd 1.4.50 and earlier allows remote attackers to leak process memory via crafted HTTP headers. The request parser retains header-value pointers when folded lines or duplicate Range processing reallocates or frees their backing buffers. Disclosure is read-only, limited to memory reused within the same request, and requires exact guesses about stable, non-attacker-controlled contents.
Summary
What happened
Use-after-free in lighttpd 1.4.50 and earlier allows remote attackers to leak process memory via crafted HTTP headers. The request parser retains header-value pointers when folded lines or duplicate Range processing reallocates or frees their backing buffers. Disclosure is read-only, limited to memory reused within the same request, and requires exact guesses about stable, non-attacker-controlled contents.
The record
- CVE
- CVE-2018-25103
- Published
- Jun 17, 2024
- Updated
- Sep 15, 2025
- Vendor
- lighttpd
- Product
- lighttpd
- Classifications
- CWE-416, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 17, 2024CVE publishedPublication date reported by the CVE source.
- Sep 15, 2025Record 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=0 <=1.4.50
- Affected versionversion=* <=1.4.50
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.
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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