CVE-2026-82209

HIGHPre-NVD 8.28.2—
EchelonGraph scoreHIGH confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-09-06. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this weekElevated
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.2Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

When libpsl support is enabled, libcurl fails to enforce the Public Suffix List boundary check when processing a Set-Cookie header where the Domain attribute explicitly matches an origin host that is itself a public suffix (e.g., Domain=co.uk set by co.uk).

Instead of coercing it into a strict host-only cookie, libcurl saves the cookie with wildcard domain scope (.co.uk). Consequently, the cookie is inappropriately included in subsequent outbound requests or HTTP redirects to arbitrary sibling subdomains under the same public suffix (e.g., attacker.co.uk).

CVSS v3
8.2
EG Score
8.2(high)
EG Risk
68(Attend)
EG Risk 68/100SSVC: Attend

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
Severity82% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
44%
KEV
Not listed

Published

September 6, 2026

Last Modified

September 15, 2026

Advisory Details (3)

Auto-updated Sep 8, 2026
No patch confirmed yet.
generic

HackerOne

https://hackerone.com/reports/3972385
generic

curl - domain-scoped PSL domain cookie - CVE-2026-82209

https://curl.se/docs/CVE-2026-82209.html
generic
https://curl.se/docs/CVE-2026-82209.json

Vendor Advisories for CVE-2026-82209(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 5 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
curl—8.22.0-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
curl—8.22.0-r0—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
curl7.88.1-10 ... 8.9.1-2~bpo12+1 (179 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.22.0~rc3-1+exp1 (79 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.22.0~rc3-1+exp1 (73 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 42× in last 7d / 69× 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.

  1. 2026-09-19 07:38 UTCVendor advisory
  2. 2026-09-19 07:37 UTCGHSA enrichment
  3. 2026-09-18 19:51 UTCEG score recompute
  4. 2026-09-18 19:51 UTCVendor advisory
  5. 2026-09-18 19:51 UTCGHSA enrichment
  6. 2026-09-18 19:28 UTCEPSS rescore
  7. 2026-09-18 08:06 UTCVendor advisory
  8. 2026-09-18 08:06 UTCGHSA enrichment
  9. 2026-09-17 20:21 UTCEG score recompute
  10. 2026-09-17 20:21 UTCVendor advisory
  11. 2026-09-17 20:21 UTCGHSA enrichment
  12. 2026-09-17 06:45 UTCVendor advisory
  13. 2026-09-17 06:45 UTCGHSA enrichment
  14. 2026-09-16 18:44 UTCEG score recompute
  15. 2026-09-16 18:44 UTCVendor advisory
  16. 2026-09-16 18:44 UTCGHSA enrichment
  17. 2026-09-16 14:08 UTCEPSS rescore
  18. 2026-09-16 06:59 UTCEG score recompute
  19. 2026-09-16 06:59 UTCVendor advisory
  20. 2026-09-16 06:59 UTCGHSA enrichment
  21. 2026-09-16 05:15 UTCEPSS rescore
  22. 2026-09-15 19:14 UTCVendor advisory
  23. 2026-09-15 19:14 UTCGHSA enrichment
  24. 2026-09-15 07:28 UTCVendor advisory
  25. 2026-09-15 07:28 UTCGHSA enrichment
Show 44 more
  1. 2026-09-15 06:32 UTCEG score recompute
  2. 2026-09-15 06:32 UTCVendor advisory
  3. 2026-09-15 06:32 UTCGHSA enrichment
  4. 2026-09-15 03:12 UTCEPSS rescore
  5. 2026-09-15 03:12 UTCEPSS rescore
  6. 2026-09-14 18:47 UTCVendor advisory
  7. 2026-09-14 18:47 UTCGHSA enrichment
  8. 2026-09-14 07:02 UTCVendor advisory
  9. 2026-09-14 07:02 UTCGHSA enrichment
  10. 2026-09-13 19:17 UTCEG score recompute
  11. 2026-09-13 19:17 UTCVendor advisory
  12. 2026-09-13 19:17 UTCGHSA enrichment
  13. 2026-09-13 07:31 UTCVendor advisory
  14. 2026-09-13 07:31 UTCGHSA enrichment
  15. 2026-09-12 19:46 UTCEG score recompute
  16. 2026-09-12 19:46 UTCVendor advisory
  17. 2026-09-12 19:46 UTCGHSA enrichment
  18. 2026-09-12 08:01 UTCVendor advisory
  19. 2026-09-12 08:01 UTCGHSA enrichment
  20. 2026-09-11 20:16 UTCVendor advisory
  21. 2026-09-11 20:16 UTCGHSA enrichment
  22. 2026-09-11 18:24 UTCEG score recompute
  23. 2026-09-11 18:24 UTCVendor advisory
  24. 2026-09-11 18:24 UTCGHSA enrichment
  25. 2026-09-11 14:53 UTCEPSS rescore
  26. 2026-09-11 14:53 UTCEPSS rescore
  27. 2026-09-11 06:39 UTCGHSA enrichment
  28. 2026-09-10 18:54 UTCEG score recompute
  29. 2026-09-10 18:54 UTCGHSA enrichment
  30. 2026-09-10 07:09 UTCGHSA enrichment
  31. 2026-09-09 19:24 UTCGHSA enrichment
  32. 2026-09-09 07:39 UTCEG score recompute
  33. 2026-09-09 07:39 UTCGHSA enrichment
  34. 2026-09-08 22:01 UTCEPSS rescore
  35. 2026-09-08 19:54 UTCEG score recompute
  36. 2026-09-08 19:54 UTCGHSA enrichment
  37. 2026-09-08 18:50 UTCEG score recompute▲ 8.20
  38. 2026-09-08 18:50 UTCGHSA enrichment
  39. 2026-09-08 18:49 UTCMITRE cvelistV5CVSS v3 → 8.2 · severity → HIGH
  40. 2026-09-08 15:01 UTCEG score recompute
  41. 2026-09-08 15:00 UTCGHSA enrichment
  42. 2026-09-06 18:20 UTCNVD update
  43. 2026-09-06 17:59 UTCEG score recompute
  44. 2026-09-06 17:58 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-82209?
CVE-2026-82209 is a high vulnerability published on September 6, 2026. When libpsl support is enabled, libcurl fails to enforce the Public Suffix List boundary check when processing a Set-Cookie header where the Domain attribute explicitly matches an origin host that is itself a public suffix (e.g., Domain=co.uk set by co.uk). Instead of coercing it into a strict…
When was CVE-2026-82209 disclosed?
CVE-2026-82209 was first published in the National Vulnerability Database on September 6, 2026, with the most recent update on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-82209 actively exploited?
CVE-2026-82209 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 55.7% of all scored CVEs.
What is the CVSS score of CVE-2026-82209?
CVE-2026-82209 has a CVSS v3.1 base score of 8.2 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-82209?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-82209, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-82209

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