CVE-2008-5428: Opera 9.51 on Windows XP does not properly handle (1) multipart/mixed e-mail messages with many MIME parts and

Routine

MEDIUM 4.3DOWNGRADE

CVE-2008-5428 is a medium-severity flaw (CVSS 4.3) affecting opera. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Opera 9.51 on Windows XP does not properly handle (1) multipart/mixed e-mail messages with many MIME parts and possibly (2) e-mail messages with many "Content-type: message/rfc822;" headers, which allows remote attackers to cause a denial of service (stack consumption or other resource consumption) via a large e-mail message, a related issue to CVE-2006-1173.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-399
Published	2008-12-11
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: opera

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

Am I affected?

Timeline

2008-12-11 15:30 UTCPublished CVE record published
2026-06-16 22:59 UTCUpdated Record last modified

opera opera DOWNGRADE

Affected: 9.51

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.51

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 9.51 (Debian / Ubuntu)

apt-cache madison opera sudo apt install opera=<VERSION_BEFORE_9.51> sudo apt-mark hold opera

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

dnf --showduplicates list opera sudo dnf downgrade opera-<VERSION_BEFORE_9.51> sudo dnf versionlock add opera

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.

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-2008-5428?

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

Is CVE-2008-5428 being exploited?

CVE-2008-5428 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-2008-5428 affect?

CVE-2008-5428 affects opera. Severity is medium (CVSS 4.3). Opera 9.51 on Windows XP does not properly handle (1) multipart/mixed e-mail messages with many MIME parts and possibly (2) e-mail messages with many "Content-type: message/rfc822;" headers, which allows remote attackers to cause a denial o

How urgent is CVE-2008-5428?

Priority 37/100. Public exploit reference

Software pages

Windows vulnerabilities

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References

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