CVE-2023-6209

Name: CVE-2023-6209
Creator: NVD / NIST
Published: 2023-11-21T15:15:07.957+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.41%

Last modified Jun 17, 2026

CVE-2023-6209 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. Relative URLs starting with three slashes were incorrectly parsed, and a path-traversal "/../" part in the path could be used to override the specified host. This could contribute to security problems in web sites. EPSS estimates a 1.41% chance of exploitation in the next 30 days.

Description

Relative URLs starting with three slashes were incorrectly parsed, and a path-traversal "/../" part in the path could be used to override the specified host. This could contribute to security problems in web sites. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS Probability

1.41%

69.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-22

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 120.0
Mozilla	Firefox Esr	< 115.5.0
Mozilla	Thunderbird	< 115.5
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0
Debian	Debian Linux	12.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1858570Issue Tracking, Permissions Required
https://lists.debian.org/debian-lts-announce/2023/11/msg00017.htmlMailing List
https://lists.debian.org/debian-lts-announce/2023/11/msg00030.html
https://www.debian.org/security/2023/dsa-5561Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2023-49/Release Notes, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-50/Release Notes, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-52/Release Notes, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1858570Issue Tracking, Permissions Required
https://lists.debian.org/debian-lts-announce/2023/11/msg00017.htmlMailing List
https://lists.debian.org/debian-lts-announce/2023/11/msg00030.html
https://www.debian.org/security/2023/dsa-5561Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2023-49/Release Notes, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-50/Release Notes, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-52/Release Notes, Vendor Advisory

Timeline

Published: Nov 21, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-6209?

How severe is CVE-2023-6209?

CVE-2023-6209 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.41% probability of exploitation in the next 30 days.

How do I fix CVE-2023-6209?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-6209?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST