CVE-2023-38545
HighPublic exploitThis flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake.
Published Nov 15, 2023 · Updated Oct 15, 2026 · Also known as ALPINE-CVE-2023-38545, CURL-CVE-2023-38545, DEBIAN-CVE-2023-38545, DSA-5523-1, JLSEC-2025-34, SUSE-SU-2023:4043-1, SUSE-SU-2023:4044-1, UBUNTU-CVE-2023-38545, USN-6429-1
Key Facts
Patch immediately- CVE-2023-38545 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Libcurl (Haxx), Active Iq Unified Manager (Netapp), Oncommand Insight (Netapp) and 22 more products.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 79% probability of exploitation in the next 30 days.
- Fixed versions are available, including cmake 3.21.4-10, cmake 3.27.8-1.1, curl 0:7.76.1-14.el9_0.9.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
79%
Higher than 99.5% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2023-38545 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Affected Products
143 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| LibcurlHaxx | See advisory | 8.4.0 |
| Active Iq Unified ManagerNetapp | See advisory | n/a |
| Oncommand InsightNetapp | See advisory | n/a |
| Oncommand Workflow AutomationNetapp | See advisory | n/a |
| FedoraFedoraproject | 37 | n/a |
Patched Releases
cmake
3.21.4-10, 3.27.8-1.1
curl
0:7.76.1-14.el9_0.9, 7.61.1-34.el8_10.3+sp999, 7.68.0-1ubuntu2.20, 7.74.0-1.3+deb11u10, 7.76.1-23.el9_2.4, 7.76.1-26.el9_3.2, 7.81.0-1ubuntu1.14, 7.88.1-10+deb12u14+sp999, 7.88.1-10+deb12u4, 8.0.1-11.74.1, 8.0.1-150400.5.32.1, 8.1.2-4.ph3, 8.1.2-6.ph4, 8.1.2-6.ph5, 8.2.1-1ubuntu3.1, 8.3.0-1.amzn2.0.4, 8.3.0-1.amzn2023.0.2, 8.3.0-2, 8.3.0-3, 8.4.0, 8.4.0-1.1, 8.4.0-r0
CURL_jll
8.5.0+0
curl-devel
8.1.2-6.ph4, 8.1.2-6.ph5
curl-libs
8.1.2-6.ph4, 8.1.2-6.ph5
curl-minimal
7.76.1-23.el9_2.4, 7.76.1-26.el9_3.2, 8.3.0-1.amzn2023.0.2
curl-rustls
8.4.0-r0
davix
0.8.5-1.1
davix-devel
0.8.5-1.1
fiona-fio
1.9.6-1.1
Libcurl
8.4.0, 7.76.1-23.el9_2.4, 7.76.1-26.el9_3.2, 8.3.0-1.amzn2.0.4, 8.3.0-1.amzn2023.0.2
jbcs-httpd24-curl
0:8.4.0-2.el7jbcs, 0:8.4.0-2.el8jbcs
LibCURL_jll
8.4.0+0
libcurl-devel
7.76.1-23.el9_2.4, 7.76.1-26.el9_3.2, 8.0.1-11.74.1, 8.0.1-150400.5.32.1, 8.3.0-1.amzn2.0.4, 8.3.0-1.amzn2023.0.2, 8.4.0-1.1
libcurl-devel-32bit
8.0.1-150400.5.32.1, 8.4.0-1.1
libcurl-minimal
7.76.1-23.el9_2.4, 7.76.1-26.el9_3.2, 8.3.0-1.amzn2023.0.2
libcurl4
8.0.1-11.74.1, 8.0.1-150400.5.32.1, 8.4.0-1.1
libcurl4-32bit
8.0.1-11.74.1, 8.0.1-150400.5.32.1, 8.4.0-1.1
libdavix0
0.8.5-1.1
Windows 10 1809
10.0.17763.5122
Windows 10 21h2
10.0.19044.3693
Windows 10 22h2
10.0.19045.3693
Windows 11 21h2
10.0.22000.2600
Windows 11 22h2
10.0.22621.2715
Windows 11 23h2
10.0.22631.2715
Timeline
Publicly disclosed
Nov 15, 2023
Last updated
Oct 15, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
- CWE-787 Out-of-bounds Write
References
- advisoryRHSA-2023:5700
- advisoryRHSA-2023:5763
- advisoryRHSA-2023:6745
- advisoryRHSA-2023:7625
- advisoryRHSA-2023:7626
FAQ
Common Questions.
This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake.
Affected: Libcurl (Haxx); Active Iq Unified Manager (Netapp); Oncommand Insight (Netapp), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including cmake 3.21.4-10, cmake 3.27.8-1.1, curl 0:7.76.1-14.el9_0.9.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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