CVE-2026-19931

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-06. 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

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.

CVSS v3
9.8
EG Score
9.8(high)
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
66%
KEV
Not listed

Published

September 6, 2026

Last Modified

September 15, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
No patch confirmed yet.
generic

HackerOne

https://hackerone.com/reports/3923520
generic
https://curl.se/docs/CVE-2026-19931.json
generic

curl - Negotiate ambient user conn reuse - CVE-2026-19931

https://curl.se/docs/CVE-2026-19931.html

Vendor Advisories for CVE-2026-19931(2)

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

Affected Packages

(5 across 5 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
curl—8.22.0-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
curl—8.22.0-r0—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
curl7.88.1-10 ... 8.9.1-2~bpo12+1 (179 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.22.0~rc3-1+exp1 (79 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.22.0~rc3-1+exp1 (73 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 100× in last 7d / 151× 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 151 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-19931?
CVE-2026-19931 is a critical vulnerability published on September 6, 2026. A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.
When was CVE-2026-19931 disclosed?
CVE-2026-19931 was first published in the National Vulnerability Database on September 6, 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-2026-19931 actively exploited?
CVE-2026-19931 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 34.2% of all scored CVEs.
What is the CVSS score of CVE-2026-19931?
CVE-2026-19931 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-19931?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-19931, 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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