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NVD / CVE Program· CNA GitHub_M

CVE-2024-23638: SQUID-2023:11 Denial of Service in Cache Manager

Noroxi assessment

Priority: Plan (action score 44/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 60% (FIRST EPSS); higher than 99.1% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: libecap (AlmaLinux:8) 1.0.1-2.module_el8.6.0+2741+01592ae8, 1.0.1-2.module_el8.6.0+3048+383bc947; libecap-devel (AlmaLinux:8) 1.0.1-2.module_el8.6.0+3048+383bc947, 1.0.1-2.module_el8.6.0+2741+01592ae8; squid (AlmaLinux:8) 7:4.15-10.module_el8.10.0+3916+ed00a4a0.3.

Add it to your regular patch cycle. Upgrade to libecap (AlmaLinux:8) 1.0.1-2.module_el8.6.0+2741+01592ae8, 1.0.1-2.module_el8.6.0+3048+383bc947; libecap-devel (AlmaLinux:8) 1.0.1-2.module_el8.6.0+3048+383bc947, 1.0.1-2.module_el8.6.0+2741+01592ae8; squid (AlmaLinux:8) 7:4.15-10.module_el8.10.0+3916+ed00a4a0.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Squid is a caching proxy for the Web. Due to an expired pointer reference bug, Squid prior to version 6.6 is vulnerable to a Denial of Service attack against Cache Manager error responses. This problem allows a trusted client to perform Denial of Service when generating error pages for Client Manager reports. Squid older than 5.0.5 have not been tested and should be assumed to be vulnerable. All Squid-5.x up to and including 5.9 are vulnerable. All Squid-6.x up to and including 6.5 are vulnerable. This bug is fixed by Squid version 6.6. In addition, patches addressing this problem for the stable releases can be found in Squid's patch archives. As a workaround, prevent access to Cache Manager using Squid's main access control: `http_access deny manager`.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Jan 23, 2024
Updated
Jun 17, 2026
EPSS
60.0% · 99th percentile

Report tools

JSON

Action score

44

Plan

Add it to your regular patch cycle.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
18 / 30 · 60.0%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
6.5
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2024-23638

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
squid-cachesquid

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • squid-cache squid5.0 and later · up to 5.9 inclusive
  • squid-cache squid6.0 and later · before 6.6

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • squid-cache squid

    • < 6.6affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8libecapbefore 1.0.1-2.module_el8.6.0+2741+01592ae81.0.1-2.module_el8.6.0+2741+01592ae8
AlmaLinux:8libecapbefore 1.0.1-2.module_el8.6.0+3048+383bc9471.0.1-2.module_el8.6.0+3048+383bc947
AlmaLinux:8libecap-develbefore 1.0.1-2.module_el8.6.0+3048+383bc9471.0.1-2.module_el8.6.0+3048+383bc947
AlmaLinux:8libecap-develbefore 1.0.1-2.module_el8.6.0+2741+01592ae81.0.1-2.module_el8.6.0+2741+01592ae8
AlmaLinux:8squidbefore 7:4.15-10.module_el8.10.0+3916+ed00a4a0.37:4.15-10.module_el8.10.0+3916+ed00a4a0.3
AlmaLinux:9squidbefore 7:5.5-13.el9_47:5.5-13.el9_4
Debian:11squidbefore 4.13-10+deb11u34.13-10+deb11u3
Debian:12squidbefore 5.7-2+deb12u15.7-2+deb12u1
Debian:13squidbefore 6.6-16.6-1
openSUSE:Leap 15.5squidbefore 5.7-150400.3.23.15.7-150400.3.23.1
openSUSE:Tumbleweedsquidbefore 6.6-2.16.6-2.1
Red Hat:enterprise_linux:8::appstreamlibecapbefore 0:1.0.1-2.module+el8.9.0+19703+a1da72230:1.0.1-2.module+el8.9.0+19703+a1da7223
Red Hat:enterprise_linux:8::appstreamlibecap-debuginfobefore 0:1.0.1-2.module+el8.9.0+19703+a1da72230:1.0.1-2.module+el8.9.0+19703+a1da7223
Red Hat:enterprise_linux:8::appstreamlibecap-debugsourcebefore 0:1.0.1-2.module+el8.9.0+19703+a1da72230:1.0.1-2.module+el8.9.0+19703+a1da7223
Red Hat:enterprise_linux:8::appstreamlibecap-develbefore 0:1.0.1-2.module+el8.9.0+19703+a1da72230:1.0.1-2.module+el8.9.0+19703+a1da7223
Red Hat:enterprise_linux:8::appstreamsquidbefore 7:4.15-10.module+el8.10.0+22489+b920747d.37:4.15-10.module+el8.10.0+22489+b920747d.3
Red Hat:enterprise_linux:8::appstreamsquid-debuginfobefore 7:4.15-10.module+el8.10.0+22489+b920747d.37:4.15-10.module+el8.10.0+22489+b920747d.3
Red Hat:enterprise_linux:8::appstreamsquid-debugsourcebefore 7:4.15-10.module+el8.10.0+22489+b920747d.37:4.15-10.module+el8.10.0+22489+b920747d.3
Red Hat:enterprise_linux:9::appstreamsquidbefore 7:5.5-13.el9_47:5.5-13.el9_4
Red Hat:enterprise_linux:9::appstreamsquid-debuginfobefore 7:5.5-13.el9_47:5.5-13.el9_4
Red Hat:enterprise_linux:9::appstreamsquid-debugsourcebefore 7:5.5-13.el9_47:5.5-13.el9_4
Rocky Linux:8libecapbefore 0:1.0.1-2.module+el8.9.0+1437+df5ea8f00:1.0.1-2.module+el8.9.0+1437+df5ea8f0
Rocky Linux:8squidbefore 7:4.15-10.module+el8.10.0+1758+80ba9f4b7:4.15-10.module+el8.10.0+1758+80ba9f4b
Rocky Linux:9squidbefore 7:5.5-13.el9_47:5.5-13.el9_4

+3

Same product

squid-cache: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-25617Denial of Service in HTTP Header parser in squid proxy
    56Plan
  • CVE-2023-49285Denial of Service in HTTP Message Processing in Squid
    56Plan
  • CVE-2021-31806An issue was discovered in Squid before 4.15 and 5.x before 5.0.6.
    55Plan

Published before and after this one in the same product

  • ← EarlierCVE-2023-49288Dec 4, 2023 · Denial of Service in HTTP Collapsed Forwarding in Squid
    31Monitor
  • ← EarlierCVE-2023-50269Dec 14, 2023 · SQUID-2023:10 Denial of Service in HTTP Request parsing
    47Plan
  • Later →CVE-2024-25111Mar 6, 2024 · SQUID-2024:1 Denial of Service in HTTP Chunked Decoding
    50Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:libecap1.0.1-2.module_el8.6.0+2741+01592ae8 · AlmaLinux:8Package registry (OSV)
almalinux:libecap-devel1.0.1-2.module_el8.6.0+2741+01592ae8 · AlmaLinux:8Package registry (OSV)
almalinux:squid7:5.5-13.el9_4 · AlmaLinux:9Package registry (OSV)
debian:squid5.7-2+deb12u1 · Debian:12Package registry (OSV)
opensuse:squid5.7-150400.3.23.1 · openSUSE:Leap 15.5Package registry (OSV)
red hat:libecap0:1.0.1-2.module+el8.9.0+19703+a1da7223 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libecap-debuginfo0:1.0.1-2.module+el8.9.0+19703+a1da7223 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libecap-debugsource0:1.0.1-2.module+el8.9.0+19703+a1da7223 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libecap-devel0:1.0.1-2.module+el8.9.0+19703+a1da7223 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:squid7:5.5-13.el9_4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:squid-debuginfo7:5.5-13.el9_4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:squid-debugsource7:5.5-13.el9_4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
rocky linux:libecap0:1.0.1-2.module+el8.9.0+1437+df5ea8f0 · Rocky Linux:8Package registry (OSV)
rocky linux:squid7:5.5-13.el9_4 · Rocky Linux:9Package registry (OSV)
suse:squid4.17-4.41.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:squid5.7-150400.3.23.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP5Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-825 · Expired Pointer Dereference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records