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Fencer Intel
medium 5.9

CVE-2023-28321 json

An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as…

published 3y ago modified 22d ago also EUVD-2023-32028 , JLSEC-2026-409

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as "Subject Alternative Name" in TLS server certificates. curl can be built to use its own name matching function for TLS rather than one provided by a TLS library. This private wildcard matching function would match IDN (International Domain Name) hosts incorrectly and could as a result accept patterns that otherwise should mismatch. IDN hostnames are converted to puny code before used for certificate checks. Puny coded names always start with `xn--` and should not be allowed to pattern match, but the wildcard check in curl could still check for `x*`, which would match even though the IDN name most likely contained nothing even resembling an `x`.

Patch / fix

  • julia CURL_jll 8.5.0+0
  • julia LibCURL_jll 8.2.1+0
  • haxx curl 8.1.0
  • apple macos 11.7.9, 12.6.8, 13.5
  • curl Debian 14, Debian 13, Debian 12 7.88.1-10

debian advisories DEBIAN-CVE-2023-28321

  • curl Ubuntu 20.04 LTS 7.68.0-1ubuntu2.19
  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.11
  • curl Ubuntu Pro 14.04 LTS 7.35.0-1ubuntu2.20+esm16
  • curl Ubuntu Pro 16.04 LTS 7.47.0-1ubuntu2.19+esm9
  • curl Ubuntu Pro 18.04 LTS 7.58.0-2ubuntu3.24+esm1

ubuntu advisories UBUNTU-CVE-2023-28321

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

  • curl RHEL 8 7.61.1-30.el8_8.3
  • libcurl RHEL 8 7.61.1-30.el8_8.3
  • libcurl-minimal RHEL 8 7.61.1-30.el8_8.3
  • jbcs-httpd24-apr jboss core services 1 1.7.0-8.el7jbcs
  • jbcs-httpd24-apr jboss core services 1 1.7.0-8.el8jbcs
  • jbcs-httpd24-curl jboss core services 1 8.2.1-1.el7jbcs
  • jbcs-httpd24-curl jboss core services 1 8.2.1-1.el8jbcs
  • jbcs-httpd24-httpd jboss core services 1 2.4.57-5.el7jbcs

red hat advisories RHSA-2023:4523RHSA-2023:4629RHSA-2023:6292RHSA-2023:5598RHSA-2023:4354

  • curl SLE Module for Basesystem 15 SP4, SLE Micro 5.4, SLE Micro 5.3 +3 more 8.0.1-150400.5.23.1
  • curl SLES 12 SP2-BCL 7.37.0-37.98.1
  • curl SLES for SAP 12 SP4, SLES 12 SP4-LTSS, SLES 12 SP4-ESPOS +2 more 7.60.0-4.56.1
  • curl SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +11 more 7.66.0-150200.4.57.1
  • curl SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS +1 more 7.60.0-150000.51.1
  • curl SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 8.0.1-11.65.2

suse advisories SUSE-SU-2023:2224-2SUSE-SU-2023:2230-1SUSE-SU-2023:2228-1SUSE-SU-2023:2227-1SUSE-SU-2023:2226-1SUSE-SU-2023:2225-1

  • curl openSUSE Tumbleweed 8.1.0-1.1

opensuse advisories openSUSE-SU-2024:12940-1

  • curl AlmaLinux 8 7.61.1-30.el8_8.3
  • libcurl AlmaLinux 8 7.61.1-30.el8_8.3
  • libcurl-minimal AlmaLinux 8 7.61.1-30.el8_8.3
  • curl AlmaLinux 9 7.76.1-23.el9_2.2
  • libcurl AlmaLinux 9 7.76.1-23.el9_2.2
  • curl-minimal AlmaLinux 9 7.76.1-23.el9_2.2
  • libcurl-minimal AlmaLinux 9 7.76.1-23.el9_2.2

almalinux advisories ALSA-2023:4523ALSA-2023:4354

  • curl Rocky Linux 8 7.61.1-30.el8_8.3

rocky linux advisories RLSA-2023:4523

  • curl Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 8.1.0-r0

alpine advisories ALPINE-CVE-2023-28321

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 8.2.1-1
  • mysql CBL-Mariner 2.0 8.0.34-1
  • rust CBL-Mariner 2.0 1.72.0-2
  • tensorflow Azure Linux 3.0 2.16.1-1

azure linux advisories AZL-26794AZL-26808AZL-26812AZL-38032

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

Is CVE-2023-28321 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2023-28321 updated cvss 5.9

curl: IDN wildcard match may lead to Improper Cerificate Validation

  • Red Hat .NET Core 3.1 on Red Hat Enterprise Linux rh-dotnet31-curl, rh-dotnet31-libcurl Red Hat Enterprise Linux 6 curl, libcurl
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 curl, libcurl
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 9) libcurl-devel 7.76.1-23.el9_2.2, curl-debuginfo 7.76.1-23.el9_2.2, curl-debugsource 7.76.1-23.el9_2.2, libcurl-debuginfo 7.76.1-23.el9_2.2, curl-minimal-debuginfo 7.76.1-23.el9_2.2, libcurl-minimal-debuginfo 7.76.1-23.el9_2.2
    fixed: vendor fix RHSA-2023:4354
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) libcurl-devel 7.76.1-14.el9_0.7, curl-debuginfo 7.76.1-14.el9_0.7, curl-debugsource 7.76.1-14.el9_0.7, libcurl-debuginfo 7.76.1-14.el9_0.7, curl-minimal-debuginfo 7.76.1-14.el9_0.7, libcurl-minimal-debuginfo 7.76.1-14.el9_0.7
    fixed: vendor fix RHSA-2023:5598
  • Red Hat Enterprise Linux BaseOS (v. 8) curl 7.61.1-30.el8_8.3, libcurl 7.61.1-30.el8_8.3, libcurl-minimal 7.61.1-30.el8_8.3
    fixed: vendor fix RHSA-2023:4523
  • Red Hat Enterprise Linux BaseOS (v. 9) curl 7.76.1-23.el9_2.2, libcurl 7.76.1-23.el9_2.2, curl-minimal 7.76.1-23.el9_2.2, libcurl-minimal 7.76.1-23.el9_2.2
    fixed: vendor fix RHSA-2023:4354
  • Red Hat Enterprise Linux BaseOS EUS (v.8.6) curl 7.61.1-22.el8_6.9, libcurl 7.61.1-22.el8_6.9, libcurl-minimal 7.61.1-22.el8_6.9
    fixed: vendor fix RHSA-2023:6292
  • Red Hat Enterprise Linux BaseOS EUS (v.9.0) curl 7.76.1-14.el9_0.7, libcurl 7.76.1-14.el9_0.7, curl-minimal 7.76.1-14.el9_0.7, libcurl-minimal 7.76.1-14.el9_0.7
    fixed: vendor fix RHSA-2023:5598
show 3 more
  • Red Hat JBoss Core Services 2.4.57
    fixed: vendor fix RHSA-2023:4628
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-curl 8.2.1-1.el7jbcs, jbcs-httpd24-libcurl 8.2.1-1.el7jbcs Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-curl 8.2.1-1.el8jbcs, jbcs-httpd24-libcurl 8.2.1-1.el8jbcs
    fixed: vendor fix RHSA-2023:4629
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apr 1.7.0-8.el7jbcs, jbcs-httpd24-httpd 2.4.57-5.el7jbcs, jbcs-httpd24-mod_md 2.4.0-25.el7jbcs, jbcs-httpd24-mod_ssl 2.4.57-5.el7jbcs, jbcs-httpd24-mod_ldap 2.4.57-5.el7jbcs, jbcs-httpd24-apr-util 1.6.1-102.el7jbcs, +17 more Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-apr 1.7.0-8.el8jbcs, jbcs-httpd24-httpd 2.4.57-5.el8jbcs, jbcs-httpd24-mod_md 2.4.0-25.el8jbcs, jbcs-httpd24-mod_ssl 2.4.57-5.el8jbcs, jbcs-httpd24-mod_ldap 2.4.57-5.el8jbcs, jbcs-httpd24-apr-util 1.6.1-102.el8jbcs, +17 more
    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 SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

1.81% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-14).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/1950627 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
julia CURL_jll
<8.5.0+0
8.5.0+0
julia LibCURL_jll
<8.2.1+0
8.2.1+0

Affected products

  • n/a https://github.com/curl/curl

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Intel 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.