What is CVE-1999-1357?

Netscape Communicator 4.04 through 4.7 (and possibly other versions) in various UNIX operating systems converts the 0x8b character to a " " sign, which could allow remote attackers to attack other clients via cross-site scripting (CSS) in CGI programs that do not filter these characters.

How severe is CVE-1999-1357?

CVE-1999-1357 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-1999-1357 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-1357?

CVE-1999-1357 primarily affects Netscape Communicator. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-1999-1357?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-1999-1357 published?

CVE-1999-1357 was published on 1999-10-05 and last updated on 2026-06-16.

CVE-1999-1357

CVE-1999-1357 is a high-severity vulnerability in Netscape Communicator with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Netscape Communicator
Published: 1999-10-05
Last modified: 2026-06-16

Description

Netscape Communicator 4.04 through 4.7 (and possibly other versions) in various UNIX operating systems converts the 0x8b character to a "<" sign, and the 0x9b character to a ">" sign, which could allow remote attackers to attack other clients via cross-site scripting (CSS) in CGI programs that do not filter these characters.

Frequently asked questions

What is CVE-1999-1357?: Netscape Communicator 4.04 through 4.7 (and possibly other versions) in various UNIX operating systems converts the 0x8b character to a "<" sign, and the 0x9b character to a ">" sign, which could allow remote attackers to attack other clients via cross-site scripting (CSS) in CGI programs that do not filter these characters.
How severe is CVE-1999-1357?: CVE-1999-1357 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-1999-1357 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-1357?: CVE-1999-1357 primarily affects Netscape Communicator. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-1999-1357?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-1999-1357 published?: CVE-1999-1357 was published on 1999-10-05 and last updated on 2026-06-16.

References

http://marc.info/?l=bugtraq&m=93915331626185&w=2

Affected products (3)

cpe:2.3:a:netscape:communicator:*:*:*:*:*:*:*:*
cpe:2.3:a:netscape:communicator:4.04:*:*:*:*:*:*:*
cpe:2.3:a:netscape:communicator:4.51:*:*:*:*:*:*:*

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