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Fencer Vulns
high 7.5

CVE-2023-5824 json

Squid: dos against http and https

published 2023-11-03 3 y ago modified 2026-11-04 4 d ago also EUVD-2023-58107

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

A flaw was found in Squid. The limits applied for validation of HTTP response headers are applied before caching. However, Squid may grow a cached HTTP response header beyond the configured maximum size, causing a stall or crash of the worker process when a large header is retrieved from the disk cache, resulting in a denial of service.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 8 8090020231130092412.a75119d5
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support 8020020240122164331.4cda2c84
  • Red Hat Red Hat Enterprise Linux 8.2 Telecommunications Update Service 8020020240122164331.4cda2c84
  • Red Hat Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions 8020020240122164331.4cda2c84
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 8040020240122165847.522a0ee4
  • Red Hat Red Hat Enterprise Linux 8.4 Telecommunications Update Service 8040020240122165847.522a0ee4
  • Red Hat Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions 8040020240122165847.522a0ee4
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support 8060020231222131040.ad008a3a
  • Red Hat Red Hat Enterprise Linux 8.8 Extended Update Support 8080020231222130009.63b34585
  • Red Hat Red Hat Enterprise Linux 9 7:5.5-6.el9_3.2
  • Red Hat Red Hat Enterprise Linux 9.0 Extended Update Support 7:5.2-1.el9_0.4
  • Red Hat Red Hat Enterprise Linux 9.2 Extended Update Support 7:5.5-5.el9_2.3
  • squid Debian 12 5.7-2+deb12u3
  • squid Debian 14, Debian 13 6.5-1

debian advisories DEBIAN-CVE-2023-5824

  • squid Ubuntu 20.04 LTS 4.10-1ubuntu1.12
  • squid Ubuntu 22.04 LTS 5.7-0ubuntu0.22.04.4
  • squid Ubuntu 24.04 LTS 6.5-1ubuntu1

ubuntu advisories UBUNTU-CVE-2023-5824

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

  • squid RHEL 8 7:4.15-7.module+el8.9.0+20806+014d88aa.3
  • libecap RHEL 8 1.0.1-2.module+el8.9.0+19703+a1da7223
  • squid RHEL 9 7:5.5-6.el9_3.2
  • squid RHEL 9.0 EUS 7:5.2-1.el9_0.4
  • squid RHEL 8.6 EUS 7:4.15-3.module+el8.6.0+21069+a1561e3d.4
  • libecap RHEL 8.8 EUS, RHEL 8.6 EUS, RHEL 8.4 TUS +5 more 1.0.1-2.module+el8.1.0+4044+36416a77
  • squid RHEL 8.2 TUS, RHEL 8.2 E4S, RHEL 8.2 AUS 7:4.4-8.module+el8.2.0+21173+22259b09.7
  • squid RHEL 8.4 TUS, RHEL 8.4 E4S, RHEL 8.4 AUS 7:4.11-4.module+el8.4.0+21174+3894a031.6

red hat advisories RHSA-2024:1153RHSA-2024:0771RHSA-2024:0772RHSA-2024:0773RHSA-2024:0397RHSA-2024:0072

  • squid SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 5.7-150400.3.41.1

suse advisories SUSE-SU-2026:4909-1

  • squid openSUSE Tumbleweed 6.4-1.1

opensuse advisories openSUSE-SU-2024:13398-1

  • squid AlmaLinux 8 7:4.15-7.module_el8.9.0+3696+b881db49.3
  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+2741+01592ae8
  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+3048+383bc947
  • squid AlmaLinux 9 7:5.5-6.el9_3.2

almalinux advisories ALSA-2023:7668ALSA-2023:7465

  • squid Rocky Linux 8 7:4.15-7.module+el8.9.0+1568+6d4fd5d4.1
  • libecap Rocky Linux 8 1.0.1-2.module+el8.9.0+1437+df5ea8f0

rocky linux advisories RLSA-2023:7668

  • squid Azure Linux 3.0 6.5-1

azure linux advisories AZL-63100

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-2023-5824 updated cvss 7.5

squid: DoS against HTTP and HTTPS

  • Red Hat Enterprise Linux 6 squid Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script
    affected: workaround, no fix planned “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.”
  • Red Hat Enterprise Linux AppStream (v. 8) squid 4.15-7.module+el8.9.0+20806+014d88aa.3, libecap 1.0.1-2.module+el8.9.0+19703+a1da7223
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2023:7668
  • Red Hat Enterprise Linux AppStream (v. 9) squid 5.5-6.el9_3.2
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2023:7465
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) squid 4.4-8.module+el8.2.0+21173+22259b09.7, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0772
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+21174+3894a031.6
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0773
  • Red Hat Enterprise Linux AppStream E4S (v. 8.2) squid 4.4-8.module+el8.2.0+21173+22259b09.7, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0772
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+21174+3894a031.6
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0773
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.15-3.module+el8.6.0+21069+a1561e3d.4
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0771
show 5 more
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.15-6.module+el8.8.0+21068+0ecbc070.3
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0397
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) squid 5.2-1.el9_0.4
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:1153
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) squid 5.5-5.el9_2.3
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0072
  • Red Hat Enterprise Linux AppStream TUS (v. 8.2) squid 4.4-8.module+el8.2.0+21173+22259b09.7, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0772
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+21174+3894a031.6
    fixed: vendor fix “Disabling the disk caching mechanism will mitigate this vulnerability. To achieve this, remove all the 'cache_dir' directives from the Squid configuration, typically in the /etc/squid/squid.conf file.” RHSA-2024:0773

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

Exploit prediction

3.28% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support
  • Red Hat Red Hat Enterprise Linux 8.2 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 8.8 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9.2 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

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.