Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Affected versions of squid are subject to a a Use-After-Free bug which can lead to a Denial of Service attack via collapsed forwarding. All versions of Squid from 3.5 up to and including 5.9 configured with "collapsed_forwarding on" are vulnerable. Configurations with "collapsed_forwarding off" or without a "collapsed_forwarding" directive are not vulnerable. This bug is fixed by Squid version 6.0.1. Users are advised to upgrade. Users unable to upgrade should remove all collapsed_forwarding lines from their squid.conf.

The remote Ubuntu 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6728-3 advisory.

    USN-6728-1 fixed vulnerabilities in Squid. The fix for CVE-2023-5824 caused Squid to crash in certain     environments on Ubuntu 20.04 LTS and was disabled in USN-6728-2. The problematic fix for CVE-2023-5824 has     now been corrected and reinstated in this update.

    We apologize for the inconvenience.



Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 20.04 LTS / 22.04 LTS / 23.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6728-1 advisory.

    Joshua Rogers discovered that Squid incorrectly handled collapsed forwarding. A remote attacker could     possibly use this issue to cause Squid to crash, resulting in a denial of service. This issue only     affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2023-49288)

    Joshua Rogers discovered that Squid incorrectly handled certain structural elements. A remote attacker     could possibly use this issue to cause Squid to crash, resulting in a denial of service. (CVE-2023-5824)

    Joshua Rogers discovered that Squid incorrectly handled Cache Manager error responses. A remote trusted     client can possibly use this issue to cause Squid to crash, resulting in a denial of service.
    (CVE-2024-23638)

    Joshua Rogers discovered that Squid incorrectly handled the HTTP Chunked decoder. A remote attacker could     possibly use this issue to cause Squid to stop responding, resulting in a denial of service.
    (CVE-2024-25111)

    Joshua Rogers discovered that Squid incorrectly handled HTTP header parsing. A remote trusted client can     possibly use this issue to cause Squid to crash, resulting in a denial of service. (CVE-2024-25617)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2024-578 advisory.

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Buffer Overread bug     Squid is vulnerable to a Denial of Service attack against Squid HTTP Message processing. This bug is fixed     by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.
    (CVE-2023-49285)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Affected versions of squid are     subject to a a Use-After-Free bug which can lead to a Denial of Service attack via collapsed forwarding.
    All versions of Squid from 3.5 up to and including 5.9 configured with collapsed_forwarding on are     vulnerable. Configurations with collapsed_forwarding off or without a collapsed_forwarding directive     are not vulnerable. This bug is fixed by Squid version 6.0.1. Users are advised to upgrade. Users unable     to upgrade should remove all collapsed_forwarding lines from their squid.conf. (CVE-2023-49288)

  - Squid is vulnerable to Denial of Service attack against HTTP and HTTPS clients due to an Improper Handling     of Structural Elements bug. (CVE-2023-5824)

  - 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`. (CVE-2024-23638)

  - Squid is a web proxy cache. Starting in version 3.5.27 and prior to version 6.8, Squid may be vulnerable     to a Denial of Service attack against HTTP Chunked decoder due to an uncontrolled recursion bug. This     problem allows a remote attacker to cause Denial of Service when sending a crafted, chunked, encoded HTTP     Message. This bug is fixed in Squid version 6.8. In addition, patches addressing this problem for the     stable releases can be found in Squid's patch archives. There is no workaround for this issue.
    (CVE-2024-25111)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 38 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-6317eaa767 advisory.

  - Squid is a caching proxy for the Web. Due to an Improper Validation of Specified Index bug, Squid versions     3.3.0.1 through 5.9 and 6.0 prior to 6.4 compiled using `--with-openssl` are vulnerable to a Denial of     Service attack against SSL Certificate validation. This problem allows a remote server to perform Denial     of Service against Squid Proxy by initiating a TLS Handshake with a specially crafted SSL Certificate in a     server certificate chain. This attack is limited to HTTPS and SSL-Bump. This bug is fixed in Squid version     6.4. In addition, patches addressing this problem for the stable releases can be found in Squid's patch     archives. Those who you use a prepackaged version of Squid should refer to the package vendor for     availability information on updated packages. (CVE-2023-46724)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a NULL pointer     dereference bug Squid is vulnerable to a Denial of Service attack against Squid's Gopher gateway. The     gopher protocol is always available and enabled in Squid prior to Squid 6.0.1. Responses triggering this     bug are possible to be received from any gopher server, even those without malicious intent. Gopher     support has been removed in Squid version 6.0.1. Users are advised to upgrade. Users unable to upgrade     should reject all gopher URL requests. (CVE-2023-46728)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Affected versions of squid are     subject to a a Use-After-Free bug which can lead to a Denial of Service attack via collapsed forwarding.
    All versions of Squid from 3.5 up to and including 5.9 configured with collapsed_forwarding on are     vulnerable. Configurations with collapsed_forwarding off or without a collapsed_forwarding directive     are not vulnerable. This bug is fixed by Squid version 6.0.1. Users are advised to upgrade. Users unable     to upgrade should remove all collapsed_forwarding lines from their squid.conf. (CVE-2023-49288)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to an Incorrect Check of     Function Return Value bug Squid is vulnerable to a Denial of Service attack against its Helper process     management. This bug is fixed by Squid version 6.5. Users are advised to upgrade. There are no known     workarounds for this vulnerability. (CVE-2023-49286)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Buffer Overread bug     Squid is vulnerable to a Denial of Service attack against Squid HTTP Message processing. This bug is fixed     by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.
    (CVE-2023-49285)

  - 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. (CVE-2023-50269)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 39 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-ab77331a34 advisory.

  - Squid is a caching proxy for the Web. Due to an Improper Validation of Specified Index bug, Squid versions     3.3.0.1 through 5.9 and 6.0 prior to 6.4 compiled using `--with-openssl` are vulnerable to a Denial of     Service attack against SSL Certificate validation. This problem allows a remote server to perform Denial     of Service against Squid Proxy by initiating a TLS Handshake with a specially crafted SSL Certificate in a     server certificate chain. This attack is limited to HTTPS and SSL-Bump. This bug is fixed in Squid version     6.4. In addition, patches addressing this problem for the stable releases can be found in Squid's patch     archives. Those who you use a prepackaged version of Squid should refer to the package vendor for     availability information on updated packages. (CVE-2023-46724)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a NULL pointer     dereference bug Squid is vulnerable to a Denial of Service attack against Squid's Gopher gateway. The     gopher protocol is always available and enabled in Squid prior to Squid 6.0.1. Responses triggering this     bug are possible to be received from any gopher server, even those without malicious intent. Gopher     support has been removed in Squid version 6.0.1. Users are advised to upgrade. Users unable to upgrade     should reject all gopher URL requests. (CVE-2023-46728)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Affected versions of squid are     subject to a a Use-After-Free bug which can lead to a Denial of Service attack via collapsed forwarding.
    All versions of Squid from 3.5 up to and including 5.9 configured with collapsed_forwarding on are     vulnerable. Configurations with collapsed_forwarding off or without a collapsed_forwarding directive     are not vulnerable. This bug is fixed by Squid version 6.0.1. Users are advised to upgrade. Users unable     to upgrade should remove all collapsed_forwarding lines from their squid.conf. (CVE-2023-49288)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to an Incorrect Check of     Function Return Value bug Squid is vulnerable to a Denial of Service attack against its Helper process     management. This bug is fixed by Squid version 6.5. Users are advised to upgrade. There are no known     workarounds for this vulnerability. (CVE-2023-49286)

  - Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Buffer Overread bug     Squid is vulnerable to a Denial of Service attack against Squid HTTP Message processing. This bug is fixed     by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.
    (CVE-2023-49285)

  - 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. (CVE-2023-50269)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
193789	Ubuntu 20.04 LTS : Squid vulnerability (USN-6728-3)	Nessus	Ubuntu Local Security Checks	high
193170	Ubuntu 20.04 LTS / 22.04 LTS / 23.10 : Squid vulnerabilities (USN-6728-1)	Nessus	Ubuntu Local Security Checks	high
192888	Amazon Linux 2023 : squid (ALAS2023-2024-578)	Nessus	Amazon Linux Local Security Checks	high
187386	Fedora 38 : squid (2023-6317eaa767)	Nessus	Fedora Local Security Checks	high
187385	Fedora 39 : squid (2023-ab77331a34)	Nessus	Fedora Local Security Checks	high

Detections

Analytics

CVE-2023-49288

high

Tenable Plugins

high

high

high

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high