CVE-2026-6276

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-13. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
20.9%
KEV
Not listed

Published

May 13, 2026

Last Modified

May 14, 2026

Advisory Details (4)

Auto-updated May 13, 2026
No patch confirmed yet.
generic

HackerOne

https://hackerone.com/reports/3671818
generic

oss-security - [ADVISORY] curl: CVE-2026-6276: stale custom cookie host causes cookie leak

http://www.openwall.com/lists/oss-security/2026/04/29/13
generic
https://curl.se/docs/CVE-2026-6276.json
generic

curl - stale custom cookie host causes cookie leak - CVE-2026-6276

https://curl.se/docs/CVE-2026-6276.html

Vendor Advisories for CVE-2026-6276(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibcurl4t64 (8.5.0-2ubuntu10.9) @ noble2026-06-28ubuntu
redhatcurl-main-8.20.0-0.1.hum12026-05-02redhat

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.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 13× in last 7d / 81× 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 181 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-6276?
CVE-2026-6276 is a high vulnerability published on May 13, 2026. Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same easy handle but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second request.…
When was CVE-2026-6276 disclosed?
CVE-2026-6276 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on May 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6276 actively exploited?
CVE-2026-6276 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 20.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6276?
CVE-2026-6276 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-6276?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6276, 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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