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Fencer Vulns
high 8.8

CVE-2023-38545 in the critical feed json

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake.

published 2023-10-18 3 y ago modified 2026-10-14 25 d ago also EUVD-2023-42344 , JLSEC-2025-34

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
78.3%
EPSS 78.3% chance of exploitation in 30 days, percentile 99.5%
public exploits
0
none known

Summary

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.

Patch / fix

  • julia CURL_jll 8.5.0+0
  • julia LibCURL_jll 8.4.0+0
  • haxx libcurl 8.4.0
  • microsoft windows_10_1809 10.0.17763.5122
  • microsoft windows_10_21h2 10.0.19044.3693
  • microsoft windows_10_22h2 10.0.19045.3693
  • microsoft windows_11_21h2 10.0.22000.2600
  • microsoft windows_11_22h2 10.0.22621.2715
  • microsoft windows_11_23h2 10.0.22631.2715
  • microsoft windows_server_2019 10.0.17763.5122
  • microsoft windows_server_2022 10.0.20348.2113
  • curl Debian 12 7.88.1-10+deb12u4
  • curl Debian 14, Debian 13 8.3.0-3

debian advisories DEBIAN-CVE-2023-38545

  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.14
  • curl Ubuntu 24.04 LTS 8.2.1-1ubuntu3.1

ubuntu advisories UBUNTU-CVE-2023-38545

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • candlepin satellite 6.14 4.3.11-1.el8sat
  • mosquitto satellite capsule 6.14, satellite 6.14 2.0.17-1.el8sat
  • puppet-agent satellite capsule 6.14, satellite 6.14, RHEL 6 SATELLITE_CLIENT 7.27.0-1.el8sat
  • puppetserver satellite capsule 6.14, satellite 6.14 7.14.0-1.el8sat
  • rubygem-grpc satellite 6.14 1.58.0-1.el8sat
  • rubygem-puma satellite 6.14 6.3.1-1.el8sat
  • rubygem-sidekiq satellite 6.14 6.5.12-1.el8sat
  • candlepin-selinux satellite 6.14 4.3.11-1.el8sat

red hat advisories RHSA-2024:0797RHSA-2023:7625RHSA-2024:2011RHSA-2023:6745RHSA-2023:5763RHSA-2023:5700

  • curl SLE Module for Basesystem 15 SP5, SLE Module for Basesystem 15 SP4, SLE Micro 5.5 +4 more 8.0.1-150400.5.32.1
  • curl SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 8.0.1-11.74.1

suse advisories SUSE-SU-2023:4044-1SUSE-SU-2023:4043-1

  • curl openSUSE Tumbleweed 8.4.0-1.1
  • cmake openSUSE Tumbleweed 3.27.8-1.1

opensuse advisories openSUSE-SU-2024:13325-1openSUSE-SU-2024:13464-1

  • curl AlmaLinux 9 7.76.1-26.el9_3.2
  • libcurl AlmaLinux 9 7.76.1-26.el9_3.2
  • curl-minimal AlmaLinux 9 7.76.1-26.el9_3.2
  • libcurl-minimal AlmaLinux 9 7.76.1-26.el9_3.2
  • curl AlmaLinux 9 7.76.1-23.el9_2.4
  • libcurl AlmaLinux 9 7.76.1-23.el9_2.4
  • curl-minimal AlmaLinux 9 7.76.1-23.el9_2.4
  • libcurl-minimal AlmaLinux 9 7.76.1-23.el9_2.4

almalinux advisories ALSA-2023:6745ALSA-2023:5763

  • curl Rocky Linux 9 7.76.1-23.el9_2.4

rocky linux advisories RLSA-2023:5763

  • curl Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 8.4.0-r0

alpine advisories ALPINE-CVE-2023-38545

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl CBL-Mariner 2.0 8.3.0-2
  • cmake CBL-Mariner 2.0, Azure Linux 3.0 3.21.4-10
  • tensorflow Azure Linux 3.0 2.16.1-1

azure linux advisories AZL-31288AZL-31501AZL-34612AZL-37886

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • libcurl-compat Arch Linux 8.4.0-1
  • curl Arch Linux 8.4.0-1
  • libcurl-gnutls Arch Linux 8.4.0-1
  • lib32-libcurl-compat Arch Linux 8.4.0-1
  • lib32-curl Arch Linux 8.4.0-1
  • lib32-libcurl-gnutls Arch Linux 8.4.0-1

arch linux advisories AVG-2845AVG-2846

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-38545 updated cvss 8.1

curl: heap based buffer overflow in the SOCKS5 proxy handshake

  • Red Hat Enterprise Linux AppStream (v. 9) libcurl-devel 7.76.1-23.el9_2.4, libcurl-devel 7.76.1-26.el9_3.2, curl-debuginfo 7.76.1-23.el9_2.4, curl-debuginfo 7.76.1-26.el9_3.2, curl-debugsource 7.76.1-23.el9_2.4, curl-debugsource 7.76.1-26.el9_3.2, +6 more
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2023:5763
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) libcurl-devel 7.76.1-14.el9_0.9, curl-debuginfo 7.76.1-14.el9_0.9, curl-debugsource 7.76.1-14.el9_0.9, libcurl-debuginfo 7.76.1-14.el9_0.9, curl-minimal-debuginfo 7.76.1-14.el9_0.9, libcurl-minimal-debuginfo 7.76.1-14.el9_0.9
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2023:5700
  • Red Hat Enterprise Linux BaseOS (v. 9) curl 7.76.1-23.el9_2.4, curl 7.76.1-26.el9_3.2, libcurl 7.76.1-23.el9_2.4, libcurl 7.76.1-26.el9_3.2, curl-minimal 7.76.1-23.el9_2.4, curl-minimal 7.76.1-26.el9_3.2, +2 more
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2023:5763
  • Red Hat Enterprise Linux BaseOS EUS (v.9.0) curl 7.76.1-14.el9_0.9, libcurl 7.76.1-14.el9_0.9, curl-minimal 7.76.1-14.el9_0.9, libcurl-minimal 7.76.1-14.el9_0.9
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2023:5700
  • Red Hat JBoss Core Services
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2023:7626
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-curl 8.4.0-2.el7jbcs, jbcs-httpd24-libcurl 8.4.0-2.el7jbcs Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-curl 8.4.0-2.el8jbcs, jbcs-httpd24-libcurl 8.4.0-2.el8jbcs
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2023:7625
  • Red Hat Satellite 6.14 for RHEL 8 puppet-agent 7.27.0-1.el8sat
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2024:0797
  • Red Hat Satellite Client 6 for RHEL 6 puppet-agent 7.27.0-1.el6sat Red Hat Satellite Client 6 for RHEL 7 puppet-agent 7.27.0-1.el7sat Red Hat Satellite Client 6 for RHEL 8 puppet-agent 7.27.0-1.el8sat Red Hat Satellite Client 6 for RHEL 9 puppet-agent 7.27.0-1.el9sat
    fixed: vendor fix “To avoid this issue, we recommend you do not use `CURLPROXY_SOCKS5_HOSTNAME` proxies with curl. Also do not set a proxy environment variable to socks5h://” RHSA-2024:2011
show 1 more
  • Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-httpd 2.4.57-7.el7jbcs, jbcs-httpd24-mod_md 2.4.24-2.el7jbcs, jbcs-httpd24-mod_ssl 2.4.57-7.el7jbcs, jbcs-httpd24-mod_ldap 2.4.57-7.el7jbcs, jbcs-httpd24-openssl 1.1.1k-16.el7jbcs, jbcs-httpd24-apr-util 1.6.1-103.el7jbcs, +21 more Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-httpd 2.4.57-7.el8jbcs, jbcs-httpd24-mod_md 2.4.24-2.el8jbcs, jbcs-httpd24-mod_ssl 2.4.57-7.el8jbcs, jbcs-httpd24-mod_ldap 2.4.57-7.el8jbcs, jbcs-httpd24-openssl 1.1.1k-16.el8jbcs, jbcs-httpd24-apr-util 1.6.1-103.el8jbcs, +21 more Red Hat Satellite 6.14 for RHEL 8 candlepin 4.3.11-1.el8sat, foreman 3.7.0.11-2.el8sat, mosquitto 2.0.17-1.el8sat, satellite 6.14.2-1.el8sat, rubygem-kafo 7.2.0-1.el8sat, rubygem-puma 6.3.1-1.el8sat, +27 more
    +4 more products
    Red Hat Satellite Client 6 for RHEL 6 rubygem-foreman_scap_client 0.5.2-1.el6sat Red Hat Satellite Client 6 for RHEL 7 rubygem-foreman_scap_client 0.5.2-1.el7sat Red Hat Satellite Client 6 for RHEL 8 rubygem-foreman_scap_client 0.5.2-1.el8sat Red Hat Satellite Client 6 for RHEL 9 rubygem-foreman_scap_client 0.5.2-1.el9sat
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-25-162-05 updated cvss 8.8

Siemens SIMATIC S7-1500 CPU family

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.5
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-26-043-04 updated cvss 8.8

Siemens Desigo CC Product Family and SENTRON Powermanager

  • Siemens Desigo CC family V6 Siemens Desigo CC family V7
    affected: vendor fix
  • Siemens Desigo CC family V8 <V8.0_QU2
    affected: fixed in V8.0 support.industry.siemens.com
  • Siemens SENTRON Powermanager V6 Siemens SENTRON Powermanager V7
    affected: vendor fix
  • Siemens SENTRON Powermanager V8 <V8.0_QU2
    affected: fixed in V8.0
  • Siemens Desigo CC family V9 Siemens SENTRON Powermanager V9
    not affected: component not present

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-24-074-05 updated cvss 6.7

Siemens RUGGEDCOM APE1808

  • Siemens RUGGEDCOM APE1808
    affected: fixed in V7.4.3

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-24-137-07 updated cvss 8.8

Siemens SIMATIC RTLS Locating Manager

  • Siemens SIMATIC RTLS Locating Manager (6GT2780-0DA00) <V3.0.1.1 Siemens SIMATIC RTLS Locating Manager (6GT2780-0DA10) <V3.0.1.1 Siemens SIMATIC RTLS Locating Manager (6GT2780-0DA20) <V3.0.1.1 Siemens SIMATIC RTLS Locating Manager (6GT2780-0DA30) <V3.0.1.1 Siemens SIMATIC RTLS Locating Manager (6GT2780-1EA10) <V3.0.1.1 Siemens SIMATIC RTLS Locating Manager (6GT2780-1EA20) <V3.0.1.1
    +1 more products
    Siemens SIMATIC RTLS Locating Manager (6GT2780-1EA30) <V3.0.1.1
    affected: fixed in V3.0.1.1, mitigation

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-24-004-01 updated cvss 9.8

Rockwell Automation FactoryTalk Activation

  • Rockwell Automation Factory Talk Activation Manager <V4.00_Utilizes_Wibu-Systems_CodeMeter_7.60c
    affected: mitigation “Users of the affected software are encouraged to apply the risk mitigations, if possible:” rockwellautomation.custhelp.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

78.32% chance of exploitation in the next 30 days, higher than 99.5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/bcdannyboy/CVE-2023-38545 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/dbrugman/CVE-2023-38545-POC referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/UTsweetyfish/CVE-2023-38545 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia CURL_jll
<8.5.0+0
8.5.0+0
julia LibCURL_jll
>=7.70.0+0, <8.4.0+0
8.4.0+0

Affected products

  • curl curl
  • Siemens RUGGEDCOM APE1808
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.