Application crash via unterminated IPv6 proxy host
Published Sep 30, 2025 · Updated Sep 30, 2025
OpenSSL HTTP client APIs contain an out-of-bounds read that allows remote attackers to crash applications via crafted IPv6 URLs. The use_proxy() function copies the bracket-stripped IPv6 authority with strncpy() but omits a terminating NUL byte before proxy-bypass matching reads the buffer. Reachability requires an application to pass an attacker-controlled URL while no_proxy is set; direct HTTP API consumers are exposed, while OCSP and CMP URLs are unlikely to be attacker-controlled.
Summary
What happened
OpenSSL HTTP client APIs contain an out-of-bounds read that allows remote attackers to crash applications via crafted IPv6 URLs. The use_proxy() function copies the bracket-stripped IPv6 authority with strncpy() but omits a terminating NUL byte before proxy-bypass matching reads the buffer. Reachability requires an application to pass an attacker-controlled URL while no_proxy is set; direct HTTP API consumers are exposed, while OCSP and CMP URLs are unlikely to be attacker-controlled.
The record
- CVE
- CVE-2025-9232
- Published
- Sep 30, 2025
- Updated
- Sep 30, 2025
- Vendor
- OpenSSL Project
- Product
- OpenSSL
- Classifications
- CWE-125, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 30, 2025CVE publishedPublication date reported by the CVE source.
- Sep 30, 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=3.0.16 <3.0.18
- Affected versionversion=3.2.4 <3.2.6
- Affected versionversion=3.3.3 <3.3.5
- Affected versionversion=3.4.0 <3.4.3
- Affected versionversion=3.5.0 <3.5.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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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