CVE-2026-11856

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-03. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this weekElevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

Successfully using libcurl to do a transfer to a specific HTTP origin (hostA) with Digest authentication and then changing the origin to a different one (hostB) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Authorization: header field meant for hostA, to hostB.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
—
EPSS
61.1%
KEV
Not listed

Published

July 3, 2026

Last Modified

July 7, 2026

Advisory Details (3)

Auto-updated Jul 19, 2026
No patch confirmed yet.
generic

HackerOne

https://hackerone.com/reports/3793260
generic
https://curl.se/docs/CVE-2026-11856.json
generic

curl - cross-origin Digest auth state leak - CVE-2026-11856

https://curl.se/docs/CVE-2026-11856.html

Vendor Advisories for CVE-2026-11856(4)

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
redhatrust-main-1.96.1-1.hum12026-07-02redhat
redhatcurl-main-8.21.0-0.1.hum12026-06-24redhat

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.

Data Freshness Timeline

(refreshed 21× in last 7d / 114× 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 114 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-11856?
CVE-2026-11856 is a critical vulnerability published on July 3, 2026. Successfully using libcurl to do a transfer to a specific HTTP origin (hostA) with Digest authentication and then changing the origin to a different one (hostB) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Authorization: header field meant for hostA, to hostB.
When was CVE-2026-11856 disclosed?
CVE-2026-11856 was first published in the National Vulnerability Database on July 3, 2026, with the most recent update on July 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-11856 actively exploited?
CVE-2026-11856 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 61.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-11856?
CVE-2026-11856 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-11856?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-11856, 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.

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