--- title: "CVE-2023-38545: Out-of-bounds Write | CubePath" description: "This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy…" language: en source: https://cubepath.com/security/cve/CVE-2023-38545 --- # CVE-2023-38545: Out-of-bounds Write | CubePath ## Description This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with. Official description from the CVE record, published by hackerone. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2023-38545) ## Key data ### CVSS 3.1 High 8.8 Score published by CISA-ADP in the CVE record. CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | Metric | Value | What it means | | ---------------------- | --------- | ----------------------------------------------------------------------------------- | | Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. | | Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. | | Privileges required | None | No account or privileges are needed. | | User interaction | Required | A user has to do something first, such as opening a file or following a link. | | Scope | Unchanged | The impact stays within the vulnerable component. | | Confidentiality impact | High | Serious or total effect on the secrecy of data. | | Integrity impact | High | Serious or total effect on the trustworthiness of data. | | Availability impact | High | Serious or total effect on availability. | CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) . ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.78317 (78.3% probability) Percentile 99.6% Scores of Nov 10, 2026 Model v2026.06.15 ### CISA assessment as of Oct 17, 2024 Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA. Exploitation Public proof of concept recorded by CISA Automatable no Technical impact total ### Weakness (CWE) CWE catalog version 5.0. CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license. - [CWE-787](https://cwe.mitre.org/data/definitions/787.html) Out-of-bounds Write ## Affected products Products listed in the CVE record, as the CNA published them. - curl - affected: 8.4.0 up to before 8.4.0 - unaffected: 7.69.0 up to before 7.69.0 ## References Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [curl.se/docs/CVE-2023-38545.html](https://curl.se/docs/CVE-2023-38545.html) - [security.netapp.com/advisory/ntap-20231027-0009](https://security.netapp.com/advisory/ntap-20231027-0009/) - [lists.fedoraproject.org/archives/list/package-announce@list…](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OGMXNRNSJ4ETDK6FRNU3J7SABXPWCHSQ/) - [secpod.com/blog/high-severity-heap-buffer-overflow-vulnerab…](https://www.secpod.com/blog/high-severity-heap-buffer-overflow-vulnerability/) - [support.apple.com/kb/HT214036](https://support.apple.com/kb/HT214036) - [support.apple.com/kb/HT214063](https://support.apple.com/kb/HT214063) - [support.apple.com/kb/HT214057](https://support.apple.com/kb/HT214057) - [support.apple.com/kb/HT214058](https://support.apple.com/kb/HT214058) - [seclists.org/fulldisclosure/2024/Jan/34](http://seclists.org/fulldisclosure/2024/Jan/34) - [seclists.org/fulldisclosure/2024/Jan/37](http://seclists.org/fulldisclosure/2024/Jan/37) - [seclists.org/fulldisclosure/2024/Jan/38](http://seclists.org/fulldisclosure/2024/Jan/38) - [security.netapp.com/advisory/ntap-20240201-0005](https://security.netapp.com/advisory/ntap-20240201-0005/) - [forum.vmssoftware.com/viewtopic.php?f=8&t=8868](https://forum.vmssoftware.com/viewtopic.php?f=8&t=8868) ## Timeline 1. ID reserved Jul 20, 2023 2. Record published Oct 18, 2023 3. Record last updated Oct 14, 2026 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 20:01 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)