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.
CVE-2026-52843
CRITICALPre-NVD 9.39.3
EchelonGraph scoreLOW confidence
This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
9.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: —CVSS: 9.3Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.3
- EG Score
- 9.3(low)
- EPSS
- —
- KEV
- Not listed
Published
July 15, 2026
Last Modified
July 15, 2026
Advisory Details (4)
Auto-updated Jul 15, 2026Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available
0.2.9
Patch available: lightpanda-io/browser 0.2.9
https://github.com/lightpanda-io/browser/releases/tag/0.2.9github_commit Patch Available
commit 2cdaac780bed (lightpanda-io/browser)
Patch available: lightpanda-io/browser 0.2.9 (contains commit 2cdaac780bed)
https://github.com/lightpanda-io/browser/commit/2cdaac780bed65db98bbb6ed2ad5bc6011863c76github_pr Patch Available
`Fetch`: cookie jar should only be included for `include` and same or…
Patch available: lightpanda-io/browser 0.2.9 (PR #2155 merged 2026-04-14)
https://github.com/lightpanda-io/browser/pull/2155github Patch Available
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-v3c2-24ccWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× 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.
- 2026-07-16 00:51 UTCEG score recompute
- 2026-07-15 20:40 UTCEG score recompute
- 2026-07-15 16:29 UTCEG score recompute
- 2026-07-15 16:29 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-346
Frequently asked(4)
What is CVE-2026-52843?
CVE-2026-52843 is a critical vulnerability 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 CVE-2026-52843 disclosed?
CVE-2026-52843 was first published in the National Vulnerability Database on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-52843?
CVE-2026-52843 has a CVSS v3 base score of 9.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-52843?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-52843, 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
Explore the affected products and dependency analysis for CVE-2026-52843
Is Your Infrastructure Affected by CVE-2026-52843?
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