CVE-2023-38545

CVE Enrichment

CVSS: 9.8 CRITICAL
EPSS: 78.69%
EPSS Percentile: 99.59%
CISA KEV: Not listed

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.

Technical Details

CVSS Version: 3.1
CNA / NVD Source: [email protected]
Published: 18-Oct-2023 11:15
Last Modified: 17-Jun-2026 13:10
EPSS Date: 2026-10-18
CWE: CWE-787

CVSS Vector


            CVSS:3.1                            AV:N /
                            AC:L /
                            PR:N /
                            UI:N /
                            S:U /
                            C:H /
                            I:H /
                            A:H

Affected Products / Versions

haxx / libcurl
Version / affected range: * · from (inclusive) 7.69.0 · before (exclusive) 8.4.0
cpe:2.3:a:haxx:libcurl:*:*:*:*:*:*:*:*
fedoraproject / fedora
Version / affected range: 37
cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
netapp / active_iq_unified_manager
Version / affected range: -
cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
netapp / active_iq_unified_manager
Version / affected range: -
cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:windows:*:*
netapp / oncommand_insight
Version / affected range: -
cpe:2.3:a:netapp:oncommand_insight:-:*:*:*:*:*:*:*
netapp / oncommand_workflow_automation
Version / affected range: -
cpe:2.3:a:netapp:oncommand_workflow_automation:-:*:*:*:*:*:*:*
microsoft / windows_10_1809
Version / affected range: * · before (exclusive) 10.0.17763.5122
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:*
microsoft / windows_10_21h2
Version / affected range: * · before (exclusive) 10.0.19044.3693
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*
microsoft / windows_10_22h2
Version / affected range: * · before (exclusive) 10.0.19045.3693
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*
microsoft / windows_11_21h2
Version / affected range: * · before (exclusive) 10.0.22000.2600
cpe:2.3:o:microsoft:windows_11_21h2:*:*:*:*:*:*:*:*
microsoft / windows_11_22h2
Version / affected range: * · before (exclusive) 10.0.22621.2715
cpe:2.3:o:microsoft:windows_11_22h2:*:*:*:*:*:*:*:*
microsoft / windows_11_23h2
Version / affected range: * · before (exclusive) 10.0.22631.2715
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*
microsoft / windows_server_2019
Version / affected range: * · before (exclusive) 10.0.17763.5122
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
microsoft / windows_server_2022
Version / affected range: * · before (exclusive) 10.0.20348.2113
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*

References

Last enrichment sync: 25-Oct-2026 03:28
Sources: NVD · FIRST EPSS · CISA KEV
Latest successful provider update; providers refresh independently.

Reported Context (1)

The cURL team published version 8.4.0 on October 11, 2023, after announcing that it includes a fix for a high severity vulnerability assigned CVE-2023-38545. CVE-2023-38545: cURL SOCKS5 Flaw Causes Heap Buffer Overflow

People (1)

Products (2)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.