CVE-2023-46847: Squid is vulnerable to a Denial of Service, where a remote attacker can perform buffer overflow attack by wri

This week

HIGH 8.6REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2023-46847 is a high-severity flaw (CVSS 8.6) affecting squid, enterprise linux, enterprise linux eus. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Squid is vulnerable to a Denial of Service, where a remote attacker can perform buffer overflow attack by writing up to 2 MB of arbitrary data to heap memory when Squid is configured to accept HTTP Digest Authentication.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.6 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	78.5% (top 1%)
CISA exploited list	No
Weakness	CWE-120
Published	2023-11-03
Last modified	2026-08-07

Publisher (CNA): Red Hat, Inc. · Vendor: redhat · squid-cache

Last updated 2026-08-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-11-03 08:15 UTCPublished CVE record published
2026-08-07 02:16 UTCUpdated Record last modified

squid-cache squid UPGRADE

Affected: >= 3.2.0.1 and < 6.4

Fixed in: 6.4

Safe to downgrade to: a release before 3.2.0.1

1. Check installed version

apt-cache policy squid || rpm -q squid || squid --version

2. UPGRADE to 6.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade squid

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade squid

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.2.0.1 (Debian / Ubuntu)

apt-cache madison squid sudo apt install squid=<VERSION_BEFORE_3.2.0.1> sudo apt-mark hold squid

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list squid sudo dnf downgrade squid-<VERSION_BEFORE_3.2.0.1> sudo dnf versionlock add squid

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat enterprise linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux eus MITIGATE

Affected: 8.6 · 8.8 · 9.0 · 9.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.6

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux for arm 64 MITIGATE

Affected: 8.0_aarch64

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0_aarch64

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux for ibm z systems MITIGATE

Affected: 8.0_s390x

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0_s390x

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux for power little endian MITIGATE

Affected: 8.0_ppc64le

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0_ppc64le

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-46847?

squid: upgrade to 6.4; enterprise linux: mitigate or apply the listed mitigation; enterprise linux eus: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-46847 being exploited?

CVE-2023-46847 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-46847 affect?

CVE-2023-46847 affects squid, enterprise linux, enterprise linux eus. Severity is high (CVSS 8.6). Squid is vulnerable to a Denial of Service, where a remote attacker can perform buffer overflow attack by writing up to 2 MB of arbitrary data to heap memory when Squid is configured to accept HTTP Digest Authentication.

How urgent is CVE-2023-46847?

Priority 65/100. High severity; EPSS top 1%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Squid vulnerabilities

Related CVEs

CVE-2026-47729 MEDIUM 6.5 UPGRADE Squid is a caching proxy for the Web
CVE-2026-50012 MEDIUM 5.5 UPGRADE Squid is a caching proxy for the Web
CVE-2025-62168 CRITICAL 10.0 UPGRADE Squid is a caching proxy for the Web
CVE-2026-33526 HIGH 7.5 UPGRADE Squid is a caching proxy for the Web
CVE-2026-32748 HIGH 7.5 UPGRADE Squid is a caching proxy for the Web

References

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