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Fencer Vulns
low 2.6

CVE-2004-2491 json

A race condition in Opera web browser 7.53 Build 3850 causes Opera to fill in the address bar before the page has been loaded, which allows…

published 2004-12-31 21 y ago modified 2026-06-16 4 mo ago also EUVD-2004-2482

cvss
2.6
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
6.3%
EPSS 6.3% chance of exploitation in 30 days, percentile 93%
public exploits
1
Exploit-DB

Summary

A race condition in Opera web browser 7.53 Build 3850 causes Opera to fill in the address bar before the page has been loaded, which allows remote attackers to spoof the URL in the address bar via the window.open and location.replace HTML parameters, which facilitates phishing attacks.

Patch / fix

Timeline

  1. First public exploit (EDB-24325)
  2. Published

Exploit prediction

6.32% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-24325 Opera Web Browser 7.53 - Location Replace URI Obfuscation remote, 2004-07-27
  • securityfocus.com http://www.securityfocus.com/bid/10810 referenced PoC, tagged "exploit" by a source, unverified
  • archives.neohapsis.com http://archives.neohapsis.com/archives/fulldisclosure/2004-07/1056.html referenced PoC, tagged "exploit" by a source, unverified
  • osvdb.org http://www.osvdb.org/8317 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 2.6 AV:N/AC:H/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.