CVE-2023-6208

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2023-11-21. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
54%
KEV
Not listed

Published

November 21, 2023

Last Modified

June 17, 2026

Advisory Details (7)

Auto-updated Aug 6, 2026
Patch available.
generic Patch Available

[SECURITY] [DLA 3674-1] thunderbird security update

https://lists.debian.org/debian-lts-announce/2023/11/msg00030.html
generic Patch Available

[SECURITY] [DLA 3661-1] firefox-esr security update

https://lists.debian.org/debian-lts-announce/2023/11/msg00017.html
generic

1855345 - (CVE-2023-6208) On X11, any page can freely write to the primary selection

https://bugzilla.mozilla.org/show_bug.cgi?id=1855345
generic

Security Vulnerabilities fixed in Thunderbird 115.5 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2023-52/
generic

Security Vulnerabilities fixed in Firefox ESR 115.5.0 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2023-50/
generic

Security Vulnerabilities fixed in Firefox 120 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2023-49/
generic

[SECURITY] [DSA 5561-1] firefox-esr security update

https://www.debian.org/security/2023/dsa-5561

Patch Availability(22)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntufirefox-mozsymbols (120.0+build2-0ubuntu0.20.04.1) @ focal2026-05-24ubuntu
ubuntuxul-ext-lightning (1:115.5.0+build1-0ubuntu0.20.04.1) @ focal2026-05-24ubuntu
redhatfirefox-0:115.5.0-1.el8_22023-11-29redhat
redhatthunderbird-0:115.5.0-1.el8_22023-11-29redhat
redhatthunderbird-0:115.5.0-1.el8_42023-11-29redhat
redhatfirefox-0:115.5.0-1.el8_42023-11-29redhat
redhatfirefox-0:115.5.0-1.el9_22023-11-29redhat
redhatfirefox-0:115.5.0-1.el8_12023-11-28redhat
redhatthunderbird-0:115.5.0-1.el8_12023-11-27redhat
redhatfirefox-0:115.5.0-1.el8_62023-11-27redhat
redhatfirefox-0:115.5.0-1.el9_02023-11-27redhat
redhatthunderbird-0:115.5.0-1.el9_22023-11-27redhat
redhatfirefox-0:115.5.0-1.el8_92023-11-27redhat
redhatfirefox-0:115.5.0-1.el9_32023-11-27redhat
redhatthunderbird-0:115.5.0-1.el9_02023-11-27redhat
redhatthunderbird-0:115.5.0-1.el7_92023-11-27redhat
redhatthunderbird-0:115.5.0-1.el8_82023-11-27redhat
redhatfirefox-0:115.5.0-1.el8_82023-11-27redhat
redhatfirefox-0:115.5.0-1.el7_92023-11-27redhat
redhatthunderbird-0:115.5.0-1.el8_62023-11-27redhat
redhatthunderbird-0:115.5.0-1.el9_32023-11-27redhat
redhatthunderbird-0:115.5.0-1.el8_92023-11-27redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(10 across 5 ecosystems)
Debian:10(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (229 versions)115.5.0esr-1~deb10u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (287 versions)1:115.5.0-1~deb10u1—
Debian:11(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (127 versions)115.5.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (164 versions)1:115.5.0-1~deb11u1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 115.5.0esr-1~deb11u1 (34 versions)115.5.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:115.5.0-1~deb11u1 (49 versions)1:115.5.0-1~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—115.5.0esr-1—
thunderbird—1:115.5.0-1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—115.5.0esr-1—
thunderbird—1:115.5.0-1—

All Vendor Advisories

(22)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 5× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 163 total refreshes for this CVE.

  1. 2026-09-24 14:01 UTCEPSS rescore
  2. 2026-09-24 14:01 UTCEPSS rescore
  3. 2026-09-23 13:46 UTCEPSS rescore
  4. 2026-09-22 15:58 UTCOSV refresh
  5. 2026-09-18 19:26 UTCEPSS rescore
  6. 2026-09-16 14:06 UTCEPSS rescore
  7. 2026-09-16 05:11 UTCEPSS rescore
  8. 2026-09-16 05:11 UTCEPSS rescore
  9. 2026-09-15 03:08 UTCEPSS rescore
  10. 2026-09-13 16:45 UTCEPSS rescore
  11. 2026-09-12 14:58 UTCEPSS rescore
  12. 2026-09-11 14:51 UTCEPSS rescore
  13. 2026-09-11 09:34 UTCEPSS rescore
  14. 2026-09-08 21:58 UTCEPSS rescore
  15. 2026-09-07 15:59 UTCEPSS rescore
  16. 2026-09-06 13:46 UTCEPSS rescore
  17. 2026-09-05 15:26 UTCEPSS rescore
  18. 2026-09-04 13:58 UTCEPSS rescore
  19. 2026-09-04 05:04 UTCEPSS rescore
  20. 2026-09-03 12:45 UTCOSV refresh
  21. 2026-09-02 14:10 UTCEPSS rescore
  22. 2026-09-01 13:52 UTCEPSS rescore
  23. 2026-09-01 04:36 UTCEPSS rescore
  24. 2026-08-30 19:15 UTCEPSS rescore
  25. 2026-08-30 01:20 UTCEPSS rescore
Show 75 more
  1. 2026-08-28 21:39 UTCEPSS rescore
  2. 2026-08-27 14:23 UTCEPSS rescore
  3. 2026-08-26 14:44 UTCEPSS rescore
  4. 2026-08-25 13:47 UTCEPSS rescore
  5. 2026-08-23 00:17 UTCEPSS rescore
  6. 2026-08-23 00:17 UTCEPSS rescore
  7. 2026-08-21 23:47 UTCEPSS rescore
  8. 2026-08-20 22:53 UTCEPSS rescore
  9. 2026-08-19 17:02 UTCEPSS rescore
  10. 2026-08-18 13:46 UTCEPSS rescore
  11. 2026-08-17 02:18 UTCOSV refresh
  12. 2026-08-16 14:54 UTCEPSS rescore
  13. 2026-08-16 02:12 UTCEPSS rescore
  14. 2026-08-15 01:28 UTCEPSS rescore
  15. 2026-08-13 21:58 UTCEPSS rescore
  16. 2026-08-12 13:49 UTCEPSS rescore
  17. 2026-08-11 13:40 UTCEPSS rescore
  18. 2026-08-10 23:58 UTCEPSS rescore
  19. 2026-08-09 13:44 UTCEPSS rescore
  20. 2026-08-08 16:35 UTCEPSS rescore
  21. 2026-08-07 16:25 UTCEPSS rescore
  22. 2026-08-06 13:45 UTCEPSS rescore
  23. 2026-08-05 19:15 UTCEPSS rescore
  24. 2026-08-05 19:15 UTCEPSS rescore
  25. 2026-08-04 10:36 UTCEPSS rescore
  26. 2026-08-03 10:34 UTCEPSS rescore
  27. 2026-08-02 02:25 UTCEPSS rescore
  28. 2026-08-02 02:25 UTCEPSS rescore
  29. 2026-08-01 20:36 UTCOSV refresh
  30. 2026-08-01 04:14 UTCEPSS rescore
  31. 2026-07-30 16:26 UTCEPSS rescore
  32. 2026-07-30 01:29 UTCEPSS rescore
  33. 2026-07-28 15:34 UTCEPSS rescore
  34. 2026-07-28 15:34 UTCEPSS rescore
  35. 2026-07-26 14:53 UTCEPSS rescore
  36. 2026-07-25 14:16 UTCEPSS rescore
  37. 2026-07-24 14:16 UTCEPSS rescore
  38. 2026-07-23 14:16 UTCEPSS rescore
  39. 2026-07-23 02:30 UTCEG score recompute
  40. 2026-07-22 23:17 UTCEG score recompute
  41. 2026-07-22 14:07 UTCEPSS rescore
  42. 2026-07-22 14:07 UTCEPSS rescore
  43. 2026-07-21 15:23 UTCEPSS rescore
  44. 2026-07-20 17:06 UTCEPSS rescore
  45. 2026-07-19 14:30 UTCEPSS rescore
  46. 2026-07-19 14:29 UTCEPSS rescore
  47. 2026-07-19 02:27 UTCEPSS rescore
  48. 2026-07-19 02:27 UTCEPSS rescore
  49. 2026-07-18 10:03 UTCEPSS rescore
  50. 2026-07-18 10:03 UTCEPSS rescore
  51. 2026-07-16 17:01 UTCEPSS rescore
  52. 2026-07-15 16:56 UTCEPSS rescore
  53. 2026-07-15 03:49 UTCOSV refresh
  54. 2026-07-15 01:59 UTCEPSS rescore
  55. 2026-07-15 01:59 UTCEPSS rescore
  56. 2026-07-13 22:28 UTCEPSS rescore
  57. 2026-07-13 22:28 UTCEPSS rescore
  58. 2026-07-13 06:11 UTCEPSS rescore
  59. 2026-07-12 05:45 UTCEPSS rescore
  60. 2026-07-12 05:45 UTCEPSS rescore
  61. 2026-07-11 08:26 UTCEPSS rescore
  62. 2026-07-09 19:08 UTCEPSS rescore
  63. 2026-07-08 15:13 UTCEPSS rescore
  64. 2026-07-07 13:45 UTCEPSS rescore
  65. 2026-07-07 13:44 UTCEPSS rescore
  66. 2026-07-06 16:26 UTCEPSS rescore
  67. 2026-07-06 16:26 UTCEPSS rescore
  68. 2026-07-06 02:22 UTCEPSS rescore
  69. 2026-07-06 02:22 UTCEPSS rescore
  70. 2026-07-05 02:29 UTCEPSS rescore
  71. 2026-07-04 06:29 UTCEPSS rescore
  72. 2026-07-01 15:05 UTCEPSS rescore
  73. 2026-06-30 23:21 UTCEPSS rescore
  74. 2026-06-30 23:21 UTCEPSS rescore
  75. 2026-06-29 14:05 UTCEPSS rescore

Related CVEs(same product + same vendor)

Frequently asked(5)

What is CVE-2023-6208?
CVE-2023-6208 is a high vulnerability published on November 21, 2023. 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…
When was CVE-2023-6208 disclosed?
CVE-2023-6208 was first published in the National Vulnerability Database on November 21, 2023, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-6208 actively exploited?
CVE-2023-6208 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 46.1% of all scored CVEs.
What is the CVSS score of CVE-2023-6208?
CVE-2023-6208 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2023-6208?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-6208, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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