CVE-2001-1491: Opera 5.11 allows remote attackers to cause a denial of service (CPU consumption and memory leak) via a web pa

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MEDIUM 5.0DOWNGRADE

CVE-2001-1491 is a medium-severity flaw (CVSS 5.0) affecting opera web browser. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Opera 5.11 allows remote attackers to cause a denial of service (CPU consumption and memory leak) via a web page with a large number of images.

Why this priority

EPSS top 6%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	7.0% (top 6%)
CISA exploited list	No
Published	2001-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: opera software

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

Am I affected?

Timeline

2001-12-31 05:00 UTCPublished CVE record published
2026-06-16 21:56 UTCUpdated Record last modified

opera software opera web browser DOWNGRADE

Affected: 5.1.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.1.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 5.1.1 (Debian / Ubuntu)

apt-cache madison opera-web-browser sudo apt install opera-web-browser=<VERSION_BEFORE_5.1.1> sudo apt-mark hold opera-web-browser

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

dnf --showduplicates list opera-web-browser sudo dnf downgrade opera-web-browser-<VERSION_BEFORE_5.1.1> sudo dnf versionlock add opera-web-browser

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: Microsoft Internet Explorer 6.0 / Mozilla 0.9.6 / Opera 5.1 - Image Count Denial of Service

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-2001-1491?

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

Is CVE-2001-1491 being exploited?

CVE-2001-1491 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-2001-1491 affect?

CVE-2001-1491 affects opera web browser. Severity is medium (CVSS 5.0). Opera 5.11 allows remote attackers to cause a denial of service (CPU consumption and memory leak) via a web page with a large number of images.

How urgent is CVE-2001-1491?

Priority 46/100. EPSS top 6%: very likely to be exploited; Public exploit reference

Related CVEs

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CVE-2002-2311 MEDIUM 6.4 DOWNGRADE DOWNGRADE Microsoft Internet Explorer 6.0 and possibly others allows remote attackers to upload arbitrary file contents
CVE-2002-1091 HIGH 7.5 DOWNGRADE DOWNGRADE Netscape 6.2.3 and earlier, and Mozilla 1.0.1, allow remote attackers to corrupt heap memory and execute arbit

References

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