CVE-2023-6208

Name: CVE-2023-6208
Creator: NVD / NIST
Published: 2023-11-21T15:15:07.9+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 0.77%

Last modified Jun 17, 2026

CVE-2023-6208 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. When using X11, text selected by the page using the Selection API was erroneously copied into the primary selection, a temporary storage not unlike the clipboard. *This bug only affects Firefox on X11. Other systems are unaffected.* This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.. EPSS estimates a 0.77% chance of exploitation in the next 30 days.

Description

When using X11, text selected by the page using the Selection API was erroneously copied into the primary selection, a temporary storage not unlike the clipboard. *This bug only affects Firefox on X11. Other systems are unaffected.* This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

0.77%

51.0th percentile

Probability of exploitation in the next 30 days. Learn more

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=1855345Issue 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=1855345Issue 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-2023-6208?

How severe is CVE-2023-6208?

CVE-2023-6208 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.77% probability of exploitation in the next 30 days.

How do I fix CVE-2023-6208?

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-2023-6208?

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

Scan your code now

Source: NVD / NIST