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
51%
KEV
Not listed

Published

July 3, 2026

Last Modified

September 15, 2026

Advisory Details (3)

Auto-updated Sep 15, 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 (7.81.0-1ubuntu1.26) @ jammy2026-09-18ubuntu
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

(6 across 6 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
curl—8.22.0-r0—
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 (178 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.22.0~rc3-1+exp1 (78 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 31× in last 7d / 134× 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 578 total refreshes for this CVE.

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

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 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-2026-11856 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 48.8% 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-11856

Explore →

Is Your Infrastructure Affected by CVE-2026-11856?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs