CVE-2026-52843

CRITICALPre-NVD 9.39.3
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (13th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
9.3EG
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: 0.2%CVSS: 9.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Lightpanda is a headless browser designed for AI and automation. Prior to 0.2.9, Lightpanda fetch() and XMLHttpRequest unconditionally attached session cookies to every HTTP request, ignoring credentials: omit, credentials: same-origin, credentials: include, and XMLHttpRequest.withCredentials, allowing an attacker-controlled origin in a Lightpanda session to issue authenticated cross-origin requests against a victim origin. This issue is fixed in version 0.2.9.

CVSS v3
9.3
EG Score
9.3CRITICALmedium confidence
EG Risk
42
EG Risk 42/100

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 (value × EchelonGraph’s weight)
Severity93% × 45%
The EG Score, 9.3 of 10.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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
0.2%
EPSS %ILE
13th
KEV
Not listed

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 (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). 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

July 15, 2026

Last Modified

July 15, 2026

Advisory Details (4)

Auto-updated Oct 8, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
GitHub advisoryMentions a patch (unverified)

fetch() and XMLHttpRequest attach session cookies to cross-origin requests regardless of credentials mode · Advisory · lightpanda-io/browser · GitHub

https://github.com/lightpanda-io/browser/security/advisories/GHSA-36mm-v3c2-24cc
GitHub release Patch Available

0.2.9

Patch available: lightpanda-io/browser 0.2.9

https://github.com/lightpanda-io/browser/releases/tag/0.2.9
GitHub pull request

`Fetch`: cookie jar should only be included for `include` and same or…

Fix merged in lightpanda-io/browser PR #2155 on 2026-04-14 — awaiting tagged release

https://github.com/lightpanda-io/browser/pull/2155
GitHub commit

commit 2cdaac780bed (lightpanda-io/browser)

Fix landed in lightpanda-io/browser commit 2cdaac780bed — awaiting tagged release

https://github.com/lightpanda-io/browser/commit/2cdaac780bed65db98bbb6ed2ad5bc6011863c76

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 35× 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 100 of 128 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. None are among the latest 100 rows. The 28 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 09:32 UTCEG score recompute
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  3. 2026-10-13 07:09 UTCEG score recompute
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  5. 2026-10-12 15:58 UTCEG score recompute
  6. 2026-10-11 19:41 UTCEG score recompute
  7. 2026-10-11 16:56 UTCEG score recompute
  8. 2026-10-11 14:19 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  10. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  12. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  13. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  15. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  16. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  17. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  18. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  19. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  20. 2026-10-01 12:40 UTCEG score recompute
  21. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  22. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  23. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  24. 2026-09-28 08:45 UTCEG score recompute
  25. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 12th percentile
Show 75 more
  1. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  2. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  3. 2026-09-24 08:50 UTCEG score recompute
  4. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  5. 2026-09-23 03:16 UTCEG score recompute
  6. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  7. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  8. 2026-09-18 04:45 UTCEG score recompute
  9. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  10. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  11. 2026-09-13 23:12 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  13. 2026-09-13 07:13 UTCEG score recompute
  14. 2026-09-11 21:46 UTCEG score recompute
  15. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  16. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  17. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  18. 2026-09-08 00:52 UTCEG score recompute
  19. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  20. 2026-09-06 17:44 UTCEG score recompute
  21. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  22. 2026-09-05 20:50 UTCEG score recompute
  23. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  24. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  25. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  26. 2026-08-30 21:19 UTCEG score recompute
  27. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  28. 2026-08-30 03:52 UTCEG score recompute
  29. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  30. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  31. 2026-08-27 21:28 UTCEG score recompute
  32. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  33. 2026-08-26 23:08 UTCEG score recompute
  34. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  35. 2026-08-24 19:33 UTCEG score recompute
  36. 2026-08-24 12:17 UTCEG score recompute
  37. 2026-08-23 01:47 UTCEG score recompute
  38. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  39. 2026-08-22 00:18 UTCEG score recompute
  40. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  41. 2026-08-20 22:59 UTCEG score recompute
  42. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  43. 2026-08-20 00:16 UTCEG score recompute
  44. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  45. 2026-08-17 16:05 UTCEG score recompute
  46. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  47. 2026-08-16 19:16 UTCEG score recompute
  48. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  49. 2026-08-16 06:16 UTCEG score recompute
  50. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  51. 2026-08-15 05:14 UTCEG score recompute
  52. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  53. 2026-08-14 00:05 UTCEG score recompute
  54. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  55. 2026-08-12 14:05 UTCEG score recompute
  56. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  57. 2026-08-11 17:06 UTCEG score recompute
  58. 2026-08-11 00:26 UTCEG score recompute
  59. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  60. 2026-08-09 14:51 UTCEG score recompute
  61. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  62. 2026-08-08 18:02 UTCEG score recompute
  63. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  64. 2026-08-07 17:03 UTCEG score recompute
  65. 2026-08-06 16:03 UTCEG score recompute
  66. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  67. 2026-08-05 23:23 UTCEG score recompute
  68. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  69. 2026-08-04 17:11 UTCEG score recompute
  70. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  71. 2026-08-04 13:01 UTCEG score recompute
  72. 2026-08-04 10:39 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  73. 2026-08-03 14:16 UTCEG score recompute
  74. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  75. 2026-08-02 04:44 UTCEG score recompute

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Frequently asked(5)

What is CVE-2026-52843?
CVE-2026-52843 is a critical-severity vulnerability; its CVE record was published on July 15, 2026. Lightpanda is a headless browser designed for AI and automation. Prior to 0.2.9, Lightpanda fetch() and XMLHttpRequest unconditionally attached session cookies to every HTTP request, ignoring credentials: omit, credentials: same-origin, credentials: include, and XMLHttpRequest.withCredentials,…
When was the CVE record for CVE-2026-52843 published?
The CVE record for CVE-2026-52843 was published on July 15, 2026. 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 July 15, 2026; the record at its source may have been updated since.
Is CVE-2026-52843 actively exploited?
CVE-2026-52843 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-52843?
CVE-2026-52843 has a CVSS base score of 9.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-52843?
A fix for CVE-2026-52843 is available: update to the fixed version the vendor names in its advisory.

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