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)
EG Risk
65(Attend)
EG Risk 65/100SSVC: 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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
21.2%
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 11× in last 7d / 56× 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 164 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

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 21.2% 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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