Skip to content
Noroxi
NVD / CVE Program· CNA GitHub_M

CVE-2023-50269: SQUID-2023:10 Denial of Service in HTTP Request parsing

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Plan (action score 47/100)

  • 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: 57.6% (FIRST EPSS); higher than 99% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • 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) 7:4.15-7.module_el8.9.0+3749+dbf371ed.10.

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) 7:4.15-7.module_el8.9.0+3749+dbf371ed.10 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 Uncontrolled Recursion bug in versions 2.6 through 2.7.STABLE9, versions 3.1 through 5.9, and versions 6.0.1 through 6.5, Squid may be vulnerable to a Denial of Service attack against HTTP Request parsing. This problem allows a remote client to perform Denial of Service attack by sending a large X-Forwarded-For header when the follow_x_forwarded_for feature is configured. 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.

Published
Dec 14, 2023
Updated
Jun 17, 2026
EPSS
57.6% · 99th percentile

Report tools

JSON

Action score

47

Plan

Add it to your regular patch cycle.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
17 / 30 · 57.6%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.5
CNA · GitHub_M
8.6
1.1 point gap

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

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-2023-50269

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

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for squid-cache records
Is your version affected? Check it

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.

We use this product, ask for help

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

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

    • >= 2.6, <= 2.7.STABLE9, >= 3.1, <= 5.9, >= 6.0.1, < 6.6affected
Affected versions · NVD (4)

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

  • squid-cache squid3.1 and later · up to 5.9 inclusive
  • squid-cache squid6.0.1 and later · up to 6.5 inclusive
  • squid-cache squid2.6
  • squid-cache squid2.7

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 7:4.15-7.module_el8.9.0+3749+dbf371ed.107:4.15-7.module_el8.9.0+3749+dbf371ed.10
AlmaLinux:9squidbefore 7:5.5-6.el9_3.87:5.5-6.el9_3.8
Alpine:v3.19squidfrom 3.1 · before 6.6-r06.6-r0
Debian:10squidbefore 4.6-1+deb10u94.6-1+deb10u9
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:7::serversquidbefore 7:3.5.20-17.el7_9.107:3.5.20-17.el7_9.10
Red Hat:enterprise_linux:7::serversquid-debuginfobefore 7:3.5.20-17.el7_9.107:3.5.20-17.el7_9.10
Red Hat:enterprise_linux:7::serversquid-migration-scriptbefore 7:3.5.20-17.el7_9.107:3.5.20-17.el7_9.10
Red Hat:enterprise_linux:7::serversquid-sysvinitbefore 7:3.5.20-17.el7_9.107:3.5.20-17.el7_9.10
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 7:4.15-7.module+el8.9.0+21530+59b09a5b.107:4.15-7.module+el8.9.0+21530+59b09a5b.10
Red Hat:enterprise_linux:8::appstreamsquid-debuginfobefore 7:4.15-7.module+el8.9.0+21530+59b09a5b.107:4.15-7.module+el8.9.0+21530+59b09a5b.10
Red Hat:enterprise_linux:8::appstreamsquid-debugsourcebefore 7:4.15-7.module+el8.9.0+21530+59b09a5b.107:4.15-7.module+el8.9.0+21530+59b09a5b.10

+29

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-2023-49286Dec 4, 2023 · Denial of Service in Helper Process management
    33Monitor
  • ← EarlierCVE-2023-49288Dec 4, 2023 · Denial of Service in HTTP Collapsed Forwarding in Squid
    31Monitor
  • Later →CVE-2024-23638Jan 23, 2024 · SQUID-2023:11 Denial of Service in Cache Manager
    44Plan

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:squid7:4.15-7.module_el8.9.0+3749+dbf371ed.10 · AlmaLinux:8Package registry (OSV)
alpine:squid6.6-r0 · Alpine:v3.19Package 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+el8.1.0+4044+36416a77 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:libecap-debuginfo0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:libecap-debugsource0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:libecap-devel0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:squid7:4.15-6.module+el8.8.0+21068+0ecbc070.3 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:squid-debuginfo7:4.15-6.module+el8.8.0+21068+0ecbc070.3 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:squid-debugsource7:4.15-6.module+el8.8.0+21068+0ecbc070.3 · Red Hat:rhel_eus:8.8::appstreamPackage registry (OSV)
red hat:squid-migration-script7:3.5.20-17.el7_9.10 · Red Hat:enterprise_linux:7::serverPackage registry (OSV)
red hat:squid-sysvinit7:3.5.20-17.el7_9.10 · Red Hat:enterprise_linux:7::serverPackage registry (OSV)
rocky linux:libecap0:1.0.1-2.module+el8.9.0+1437+df5ea8f0 · Rocky Linux:8Package 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.

Patch and commit links

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

Variant candidates

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

  • CVE-2024-2511183 days apartSQUID-2024:1 Denial of Service in HTTP Chunked Decoding
    50Plan

Not on record for this CVE: EPSS history · researcher credit · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • 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
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-674 · Uncontrolled Recursion

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/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.

ATT&CK techniques

—

References

Show all references (6 more)

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

All records