Heap corruption via oversized SOCKS5 hostname copy
Published Oct 18, 2023 · Updated Jul 14, 2026
Heap-based buffer overflow in curl and libcurl 7.69.0 through 8.3.0 allows remote attackers to corrupt heap memory via a crafted URL. The SOCKS5 state machine can retain the remote-resolution flag during a slow handshake, then copy a hostname longer than the download buffer instead of a resolved address. Exploitation requires SOCKS5 hostname resolution, a sufficiently small receive buffer, and client interaction with an attacker-controlled URL; the overflow can terminate the process or corrupt adjacent heap data.
Summary
What happened
Heap-based buffer overflow in curl and libcurl 7.69.0 through 8.3.0 allows remote attackers to corrupt heap memory via a crafted URL. The SOCKS5 state machine can retain the remote-resolution flag during a slow handshake, then copy a hostname longer than the download buffer instead of a resolved address. Exploitation requires SOCKS5 hostname resolution, a sufficiently small receive buffer, and client interaction with an attacker-controlled URL; the overflow can terminate the process or corrupt adjacent heap data.
The record
- CVE
- CVE-2023-38545
- Published
- Oct 18, 2023
- Updated
- Jul 14, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-122, CWE-787, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 18, 2023CVE publishedPublication date reported by the CVE source.
- Jul 14, 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?
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- Affected versionversion=V3.1.5 <*
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.
Weakness, pattern, technique
Public exploit references
- UTsweetyfish libcurl overflow proof of conceptproof of concept · unverified
- bcdannyboy local curl proof of conceptproof of concept · unverified
- dbrugman curl command-line proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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