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Fencer Vulns
medium 5.9

CVE-2023-28320 json

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, s…

published 2023-05-26 3 y ago modified 2026-10-23 16 d ago also EUVD-2023-32027 , JLSEC-2026-408

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`. When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.

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-2023-28320

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

alpine advisories ALPINE-CVE-2023-28320

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

  • cmake CBL-Mariner 2.0 3.21.4-11
  • 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
  • cmake Azure Linux 3.0 3.28.2-1
  • tensorflow Azure Linux 3.0 2.16.1-1

azure linux advisories AZL-26790AZL-26793AZL-26809AZL-26813AZL-34605AZL-38926

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

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-2023-28320 updated cvss 3.7

curl: siglongjmp race condition may lead to crash

  • 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 JBoss Core Services 2.4.57
    fixed: vendor fix RHSA-2023:4628
  • Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal Red Hat Enterprise Linux 9 curl, libcurl, curl-minimal, libcurl-minimal
    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
21 mo ago

Exploit prediction

2.66% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/1929597 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:N/A:H
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

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-400 Uncontrolled Resource Consumption
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

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.