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CVE-2019-18677· NVD / CVE Program· CNA mitre

An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because the appended characters do not prop

Noroxi assessment

Priority: Monitor (action score 26/100)

  • 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: 7.2% (FIRST EPSS); higher than 94.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: libecap (AlmaLinux:8) 1.0.1-2.module_el8.6.0+2741+01592ae8; libecap-devel (AlmaLinux:8) 1.0.1-2.module_el8.6.0+2741+01592ae8; squid (Debian:10) 4.6-1+deb10u2.

Low priority for now. Upgrade to libecap (AlmaLinux:8) 1.0.1-2.module_el8.6.0+2741+01592ae8; libecap-devel (AlmaLinux:8) 1.0.1-2.module_el8.6.0+2741+01592ae8; squid (Debian:10) 4.6-1+deb10u2 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

An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because the appended characters do not properly interact with hostname length restrictions). Due to incorrect message processing, it can inappropriately redirect traffic to origins it should not be delivered to.

MediumCVSS 6.1 · v3.1—No exploit Fix available
Published
Nov 26, 2019
Updated
Jun 16, 2026
EPSS
7.2% · 94th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 7.2%

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-2019-18677

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
canonicalubuntu linux
fedoraprojectfedora

Affected versions

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

  • canonical ubuntu linux16.04
  • canonical ubuntu linux18.04
  • canonical ubuntu linux19.04
  • canonical ubuntu linux19.10
  • fedoraproject fedora30
  • fedoraproject fedora31
  • squid-cache squid4.0 and later · up to 4.8 inclusive
  • squid-cache squid3.0 and later · up to 3.5.28 inclusive
  • squid-cache squid2.0 and later · up to 2.7 inclusive
  • 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:8libecap-develbefore 1.0.1-2.module_el8.6.0+2741+01592ae81.0.1-2.module_el8.6.0+2741+01592ae8
Debian:10squidbefore 4.6-1+deb10u24.6-1+deb10u2
Debian:12squidbefore 4.9-14.9-1
Debian:8squid3before 3.4.8-6+deb8u93.4.8-6+deb8u9
Debian:9squid3before 3.5.23-5+deb9u23.5.23-5+deb9u2
openSUSE:Leap 15.0squidbefore 4.9-lp150.13.14.9-lp150.13.1
openSUSE:Leap 15.1squidbefore 4.9-lp151.2.7.14.9-lp151.2.7.1
Red Hat:enterprise_linux:8::appstreamlibecapbefore 0:1.0.1-2.module+el8.1.0+4044+36416a770:1.0.1-2.module+el8.1.0+4044+36416a77
Red Hat:enterprise_linux:8::appstreamlibecap-debuginfobefore 0:1.0.1-2.module+el8.1.0+4044+36416a770:1.0.1-2.module+el8.1.0+4044+36416a77
Red Hat:enterprise_linux:8::appstreamlibecap-debugsourcebefore 0:1.0.1-2.module+el8.1.0+4044+36416a770:1.0.1-2.module+el8.1.0+4044+36416a77
Red Hat:enterprise_linux:8::appstreamlibecap-develbefore 0:1.0.1-2.module+el8.1.0+4044+36416a770:1.0.1-2.module+el8.1.0+4044+36416a77
Red Hat:enterprise_linux:8::appstreamsquidbefore 7:4.11-3.module+el8.3.0+7851+7808b5f97:4.11-3.module+el8.3.0+7851+7808b5f9
Red Hat:enterprise_linux:8::appstreamsquid-debuginfobefore 7:4.11-3.module+el8.3.0+7851+7808b5f97:4.11-3.module+el8.3.0+7851+7808b5f9
Red Hat:enterprise_linux:8::appstreamsquid-debugsourcebefore 7:4.11-3.module+el8.3.0+7851+7808b5f97:4.11-3.module+el8.3.0+7851+7808b5f9
Rocky Linux:8libecapbefore 0:1.0.1-2.module+el8.4.0+404+316a0dc50:1.0.1-2.module+el8.4.0+404+316a0dc5
SUSE:HPE Helion OpenStack 8squidbefore 3.5.21-26.20.13.5.21-26.20.1
SUSE:Linux Enterprise Module for Server Applications 15squidbefore 4.9-5.11.14.9-5.11.1
SUSE:Linux Enterprise Point of Sale 11 SP3squid3before 3.1.23-8.16.37.12.13.1.23-8.16.37.12.1
SUSE:Linux Enterprise Server 12 SP5squidbefore 4.9-4.3.24.9-4.3.2

Same product

squid-cache: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-46847Squid: denial of service in http digest authentication
    57Plan
  • 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
  • CVE-2020-8450An issue was discovered in Squid before 4.10.
    51Plan
  • CVE-2024-25111SQUID-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)
debian:squid4.9-1 · Debian:12Package registry (OSV)
debian:squid33.4.8-6+deb8u9 · Debian:8Package registry (OSV)
opensuse:squid4.9-lp150.13.1 · openSUSE:Leap 15.0Package registry (OSV)
red hat:libecap0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libecap-debuginfo0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libecap-debugsource0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libecap-devel0:1.0.1-2.module+el8.1.0+4044+36416a77 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:squid7:4.11-3.module+el8.3.0+7851+7808b5f9 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:squid-debuginfo7:4.11-3.module+el8.3.0+7851+7808b5f9 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:squid-debugsource7:4.11-3.module+el8.3.0+7851+7808b5f9 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:libecap0:1.0.1-2.module+el8.4.0+404+316a0dc5 · Rocky Linux:8Package registry (OSV)
suse:squid4.9-5.11.1 · SUSE:Linux Enterprise Module for Server Applications 15Package registry (OSV)
suse:squid33.1.23-8.16.37.12.1 · SUSE:Linux Enterprise Point of Sale 11 SP3Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-352 · Cross-Site Request Forgery (CSRF)

CVSS vector

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

nvd-primary

Root cause

State-changing requests rely on the session cookie the browser sends automatically; nothing verifies that the request came from the user’s own page.

The bug in code

The whole CWE-352 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
app.use(session({ cookie: { httpOnly: true } }));app.post("/account/address", updateAddress);

Fixed

ts
app.use(session({ cookie: { httpOnly: true, sameSite: "lax" } }));app.post("/account/address", csrfProtection, updateAddress);

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

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (10 more)

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

All records