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Fencer Vulns
medium 4.3

CVE-2009-3978 json

The nsGIFDecoder2::GifWrite function in decoders/gif/nsGIFDecoder2.cpp in libpr0n in Mozilla Firefox before 3.5.5 allows remote attackers t…

published 2009-11-19 16 y ago modified 2026-06-16 4 mo ago also EUVD-2009-3949

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

The nsGIFDecoder2::GifWrite function in decoders/gif/nsGIFDecoder2.cpp in libpr0n in Mozilla Firefox before 3.5.5 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via an animated GIF file with a large image size, a different vulnerability than CVE-2009-3373.

Patch / fix

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-3978 updated cvss 4.3

Seamonkey: NULL pointer dereference in GIF decoder

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.79% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

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.