CVE-2004-1558: Multiple stack-based buffer overflows in YPOPs! (aka YahooPOPS) 0.4 through 0.6 allow remote attackers to caus

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HIGH 7.5DOWNGRADE

CVE-2004-1558 is a high-severity flaw (CVSS 7.5) affecting ypops. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple stack-based buffer overflows in YPOPs! (aka YahooPOPS) 0.4 through 0.6 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long (1) POP3 USER command or (2) SMTP request.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	71.1% (top 1%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: ypops

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

Am I affected?

Timeline

2004-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:07 UTCUpdated Record last modified

ypops ypops DOWNGRADE

Affected: 0.4 · 0.4.1 · 0.4.2 · 0.4.3 · 0.4.4 · 0.4.5 · 0.4.6 · 0.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.4 (Debian / Ubuntu)

apt-cache madison ypops sudo apt install ypops=<VERSION_BEFORE_0.4> sudo apt-mark hold ypops

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

dnf --showduplicates list ypops sudo dnf downgrade ypops-<VERSION_BEFORE_0.4> sudo dnf versionlock add ypops

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: YahooPOPs (YPOPS) 0.6 - Remote Buffer Overflow (Metasploit)
Exploit-DB: YahooPOPs 1.6 - SMTP Port Buffer Overflow
Exploit-DB: YahooPOPs 1.6 - SMTP Remote Buffer Overflow
Metasploit: YPOPS 0.6 Buffer Overflow

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-2004-1558?

ypops: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2004-1558 being exploited?

CVE-2004-1558 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-2004-1558 affect?

CVE-2004-1558 affects ypops. Severity is high (CVSS 7.5). Multiple stack-based buffer overflows in YPOPs! (aka YahooPOPS) 0.4 through 0.6 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long (1) POP3 USER command or (2) SMTP request.

How urgent is CVE-2004-1558?

Priority 56/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference

References

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