CVE-2020-26239

HIGHNVD 7.67.6
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 7.6 under NVD CVSS v3. EPSS exploit probability: 1.0% (63rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3

Also known asEUVD-2020-18845 (ENISA EUVD)Source: ENISA EUVD

7.6EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 7.6Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Scratch Addons is a WebExtension that supports both Chrome and Firefox. Scratch Addons before version 1.3.2 is vulnerable to DOM-based XSS. If the victim visited a specific website, the More Links addon of the Scratch Addons extension used incorrect regular expression which caused the HTML-escaped values to be unescaped, leading to XSS. Scratch Addons version 1.3.2 fixes the bug. The extension will be automatically updated by the browser. More Links addon can be disabled via the option of the extension.

CVSS v3
7.6
EG Score
7.6HIGHmedium confidence
EG Risk
35
EG Risk 35/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity76% × 45%
Impact severity (EG Severity): CVSS 7.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.0% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
1.0%
EPSS %ILE
63rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.6): severity, escalated by confirmed exploitation. This CVE's 7.6 is its impact severity (EG Severity), not escalated.

EG Severity
7.6 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
1.0% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

November 23, 2020

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Oct 21, 2026
Patch available. Sources: github_commit, github_release, github.
GitHub advisoryMentions a patch (unverified)

DOM-based Cross-Site Scripting · Advisory · ScratchAddons/ScratchAddons · GitHub

https://github.com/ScratchAddons/ScratchAddons/security/advisories/GHSA-6qfq-px3r-xj4p
GitHub release Patch Available

Scratch Addons v1.3.2

Patch available: ScratchAddons/ScratchAddons v1.3.2

https://github.com/ScratchAddons/ScratchAddons/releases/tag/v1.3.2
GitHub commit Patch Available

commit b9a52d6532c8 (ScratchAddons/ScratchAddons)

Patch available: ScratchAddons/ScratchAddons v1.34.0 (contains commit b9a52d6532c8)

https://github.com/ScratchAddons/ScratchAddons/commit/b9a52d6532c8514254c7cc1d8e18710dbedc41ff
Web page

ScratchAddons/addons/more-links/userscript.js at a471893df403f86c9182970678175d4772a0690c · ScratchAddons/ScratchAddons · GitHub

https://github.com/ScratchAddons/ScratchAddons/blob/a471893df403f86c9182970678175d4772a0690c/addons/more-links/userscript.js#L15

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 37× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 98 of 187 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 100 are merged into the row they repeat. The 89 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:36 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  2. 2026-11-01 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  3. 2026-10-31 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  4. 2026-10-30 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  5. 2026-10-29 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  6. 2026-10-28 19:45 UTCEG score recompute
  7. 2026-10-28 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  8. 2026-10-27 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  9. 2026-10-26 16:27 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  10. 2026-10-25 18:46 UTCEG score recompute
  11. 2026-10-25 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  12. 2026-10-24 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  13. 2026-10-23 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  14. 2026-10-22 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  15. 2026-10-21 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  16. 2026-10-21 12:20 UTCEG score recompute
  17. 2026-10-20 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  18. 2026-10-19 16:27 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  19. 2026-10-18 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  20. 2026-10-18 09:26 UTCEG score recompute
  21. 2026-10-17 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  22. 2026-10-16 16:33 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  23. 2026-10-15 16:27 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  24. 2026-10-14 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  25. 2026-10-13 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
Show 73 more
  1. 2026-10-12 19:39 UTCEG score recompute
  2. 2026-10-12 16:29 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  3. 2026-10-12 00:03 UTCEG score recompute
  4. 2026-10-11 13:43 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  5. 2026-10-10 19:56 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  6. 2026-10-09 20:04 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  7. 2026-10-09 14:28 UTCOSV refresh
  8. 2026-10-08 16:38 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  9. 2026-10-07 23:44 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  10. 2026-10-06 15:13 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  11. 2026-10-05 17:39 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  12. 2026-10-04 23:18 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  13. 2026-10-03 14:22 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  14. 2026-09-30 15:16 UTCEG score recompute
  15. 2026-09-30 14:59 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  16. 2026-09-29 15:14 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  17. 2026-09-27 13:41 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  18. 2026-09-26 15:54 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  19. 2026-09-24 14:00 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  20. 2026-09-22 14:43 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  21. 2026-09-21 20:28 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  22. 2026-09-19 21:52 UTCOSV refresh
  23. 2026-09-19 15:37 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  24. 2026-09-18 19:23 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  25. 2026-09-17 19:22 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  26. 2026-09-16 14:04 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  27. 2026-09-15 03:06 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  28. 2026-09-13 16:43 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  29. 2026-09-12 14:57 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  30. 2026-09-11 09:32 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  31. 2026-09-08 21:56 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  32. 2026-09-07 15:57 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  33. 2026-09-06 13:44 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  34. 2026-09-05 15:24 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  35. 2026-09-04 13:57 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  36. 2026-09-04 05:03 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  37. 2026-09-02 14:08 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  38. 2026-09-01 03:32 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  39. 2026-09-01 01:34 UTCOSV refresh
  40. 2026-08-30 19:14 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  41. 2026-08-30 01:18 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  42. 2026-08-27 14:21 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  43. 2026-08-26 14:42 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  44. 2026-08-25 13:45 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  45. 2026-08-21 23:45 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  46. 2026-08-20 22:52 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  47. 2026-08-19 17:00 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  48. 2026-08-18 13:44 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  49. 2026-08-17 13:43 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  50. 2026-08-16 14:52 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  51. 2026-08-16 02:11 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  52. 2026-08-15 01:26 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  53. 2026-08-15 01:22 UTCOSV refresh
  54. 2026-08-13 21:57 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  55. 2026-08-12 13:47 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  56. 2026-08-09 13:43 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  57. 2026-08-08 16:33 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  58. 2026-08-07 16:23 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  59. 2026-08-06 13:43 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  60. 2026-08-04 15:06 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  61. 2026-08-04 10:34 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  62. 2026-08-02 02:23 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  63. 2026-08-01 04:12 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  64. 2026-07-30 16:25 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  65. 2026-07-30 13:44 UTCOSV refresh
  66. 2026-07-30 01:27 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  67. 2026-07-28 15:33 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  68. 2026-07-26 14:51 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  69. 2026-07-25 14:15 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  70. 2026-07-24 14:14 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  71. 2026-07-23 14:15 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  72. 2026-07-23 01:51 UTCEG score recompute
  73. 2026-07-22 22:37 UTCEG score recompute

Frequently asked(5)

What is CVE-2020-26239?
CVE-2020-26239 is a high-severity vulnerability; its CVE record was published on November 23, 2020. Scratch Addons is a WebExtension that supports both Chrome and Firefox. Scratch Addons before version 1.3.2 is vulnerable to DOM-based XSS. If the victim visited a specific website, the More Links addon of the Scratch Addons extension used incorrect regular expression which caused the HTML-escaped…
When was the CVE record for CVE-2020-26239 published?
The CVE record for CVE-2020-26239 was published on November 23, 2020. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2020-26239 actively exploited?
CVE-2020-26239 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (63rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2020-26239?
CVE-2020-26239 has a CVSS v3 base score of 7.6 (NVD).
How do I remediate CVE-2020-26239?
A fix for CVE-2020-26239 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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