CVE-2026-11856

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM 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 — 4 sources updated this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: Elevated riskExposed: 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(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: 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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
46%
KEV
Not listed

Published

July 3, 2026

Last Modified

July 7, 2026

Advisory Details (3)

Auto-updated Aug 23, 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(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibcurl4-openssl-dev (7.35.0-1ubuntu2.20+esm22) @ trusty2026-08-25ubuntu
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.

Affected Packages

(5 across 5 ecosystems)
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
curl—8.21.0-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
curl7.74.0-1.3 ... 8.9.1-2~bpo12+1 (219 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
curl7.88.1-10 ... 8.9.1-2~bpo12+1 (174 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.21.0~rc3-1+exp1 (74 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.21.0~rc2-1+exp1 (61 versions)8.21.0~rc3-1—

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 75× in last 7d / 375× 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 507 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

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 1% probability of exploitation in the next 30 days, which ranks it in the top 53.7% of all scored CVEs.
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.

Dependency Blast Radius

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