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CVE-2023-38545

Exploitation: poc CVSS 8.8 HIGH

CVSS base score: 8.8 (High) CISA · v3.1

Score assigned by CISA's Vulnrichment program; the vendor's CVE record did not include one.

Vendor: curl   Product: curl

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.

Lifecycle Timeline

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 165 points from 2023-10-21, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 90.1% on 2025-03-22.

Published Applicability

Red Hat CSAF/VEX 0 affected · 253 fixed · 215 not affected
OSV.dev (incl. GHSA) 3 affected · 3 fixed · 0 not affected
CVE List v5 (CNA container) 1 affected · 0 fixed · 1 not affected
CVE List v5 (ADP/Vulnrichment) 4 affected · 0 fixed · 0 not affected

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

No mentions found in monitored research blogs or news feeds.

Detection & Exploitation

Exploit / Pen Test
Network IDS/IPS
none published
Host / SIEM
none published

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

Distribution Status

Debian · curl bookworm 7.88.1-10+deb12u4 trixie 8.3.0-3 forky 8.3.0-3 sid 8.3.0-3 scope: local

Where the distribution has shipped a fix, and in which version. Green means the release has resolved it, amber that it is still open. Data from the Debian Security Tracker, used under Debian's MIT / GPLv2+ terms. Debian is upstream of several other distributions, so a fix here often precedes theirs.

CISA Assessment (Vulnrichment / SSVC)

poc
no
total
8.8 HIGH
—
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE-787 — Out-of-bounds Write
2024-10-17

D3FEND Countermeasures

Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-787) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.

Listed By

SourceDateRecord
CISA Vulnrichment 2024-10-17 source record →

Referenced in Advisories

DateAdvisoryIssuer
2024-10-10 Update on SVR Cyber Operations and Vulnerability Exploitation NSA
2024-04-16 2024-038: Critical vulnerabilities in Junos OS and Junos OS Evolved CERT-EU

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References