CVE-2004-0918: The asn_parse_header function (asn1.c) in the SNMP module for Squid Web Proxy Cache before 2.4.STABLE7 allows

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MEDIUM 5.0WATCHLISTDOWNGRADEDOWNGRADEMITIGATE

CVE-2004-0918 is a medium-severity flaw (CVSS 5.0) affecting openpkg, squid, linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The asn_parse_header function (asn1.c) in the SNMP module for Squid Web Proxy Cache before 2.4.STABLE7 allows remote attackers to cause a denial of service (server restart) via certain SNMP packets with negative length fields that trigger a memory allocation error.

Why this priority

EPSS top 3%: very likely to be exploited
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	15.8% (top 3%)
CISA exploited list	No
Weakness	CWE-399
Published	2005-01-27
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: gentoo · openpkg · redhat · squid · trustix · ubuntu

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2005-01-27 05:00 UTCPublished CVE record published
2026-06-16 22:06 UTCUpdated Record last modified

openpkg openpkg DOWNGRADE

Affected: 2.1 · 2.2 · current

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1 (Debian / Ubuntu)

apt-cache madison openpkg sudo apt install openpkg=<VERSION_BEFORE_2.1> sudo apt-mark hold openpkg

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openpkg sudo dnf downgrade openpkg-<VERSION_BEFORE_2.1> sudo dnf versionlock add openpkg

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.

squid squid DOWNGRADE

Affected: 2.0_patch2 · 2.1_patch2 · 2.3_.stable4 · 2.3_.stable5 · 2.4 · 2.4_.stable2 · 2.4_.stable6 · 2.4_.stable7

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0_patch2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.0_patch2 (Debian / Ubuntu)

apt-cache madison squid sudo apt install squid=<VERSION_BEFORE_2.0_patch2> sudo apt-mark hold squid

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list squid sudo dnf downgrade squid-<VERSION_BEFORE_2.0_patch2> 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.

gentoo linux MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

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 fedora core MITIGATE

Affected: core_2.0

Fixed in: no fixed release known

Safe to downgrade to: a release before core_2.0

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.

trustix secure linux MITIGATE

Affected: 1.5 · 2.0 · 2.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.5

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.

ubuntu ubuntu linux MITIGATE

Affected: 4.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1

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-2004-0918?

openpkg: downgrade or apply the listed mitigation; squid: downgrade or apply the listed mitigation; linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2004-0918 being exploited?

CVE-2004-0918 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-2004-0918 affect?

CVE-2004-0918 affects openpkg, squid, linux. Severity is medium (CVSS 5.0). The asn_parse_header function (asn1.c) in the SNMP module for Squid Web Proxy Cache before 2.4.STABLE7 allows remote attackers to cause a denial of service (server restart) via certain SNMP packets with negative length fields that trigger a

How urgent is CVE-2004-0918?

Priority 47/100. EPSS top 3%: very likely to be exploited; On your watchlist

Software pages

Ubuntu vulnerabilities · Squid vulnerabilities

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References

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