CVE-2026-3783Public exploitNetwork attack vector

OAuth2 token disclosure via redirected netrc host

Published Mar 11, 2026 · Updated Mar 11, 2026

Credential disclosure in curl 7.33.0 through 8.18.0 allows remote attackers to obtain OAuth2 bearer tokens via cross-host redirects. In lib/http.c, output_auth_headers sends the Bearer header without checking Curl_auth_allowed_to_host when the redirected host matches a .netrc machine or default entry. Exploitation requires a bearer-authenticated transfer, redirect following, and enabled .netrc data for the destination; the receiving host obtains the token within its original authorization scope.

CVSS severity5.3
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Credential disclosure in curl 7.33.0 through 8.18.0 allows remote attackers to obtain OAuth2 bearer tokens via cross-host redirects. In lib/http.c, output_auth_headers sends the Bearer header without checking Curl_auth_allowed_to_host when the redirected host matches a .netrc machine or default entry. Exploitation requires a bearer-authenticated transfer, redirect following, and enabled .netrc data for the destination; the receiving host obtains the token within its original authorization scope.

The record

CVE
CVE-2026-3783
Published
Mar 11, 2026
Updated
Mar 11, 2026
Vendor
curl
Product
curl
Classifications
CWE-522
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.33.0 <=7.33.0
  2. Affected versionversion=7.34.0 <=7.34.0
  3. Affected versionversion=7.35.0 <=7.35.0
  4. Affected versionversion=7.36.0 <=7.36.0
  5. Affected versionversion=7.37.0 <=7.37.0
  6. Affected versionversion=7.37.1 <=7.37.1
  7. Affected versionversion=7.38.0 <=7.38.0
  8. Affected versionversion=7.39.0 <=7.39.0
  9. Affected versionversion=7.40.0 <=7.40.0
  10. Affected versionversion=7.41.0 <=7.41.0
  11. Affected versionversion=7.42.0 <=7.42.0
  12. Affected versionversion=7.42.1 <=7.42.1
  13. Affected versionversion=7.43.0 <=7.43.0
  14. Affected versionversion=7.44.0 <=7.44.0
  15. Affected versionversion=7.45.0 <=7.45.0
  16. Affected versionversion=7.46.0 <=7.46.0
  17. Affected versionversion=7.47.0 <=7.47.0
  18. Affected versionversion=7.47.1 <=7.47.1
  19. Affected versionversion=7.48.0 <=7.48.0
  20. Affected versionversion=7.49.0 <=7.49.0
  21. Affected versionversion=7.49.1 <=7.49.1
  22. Affected versionversion=7.50.0 <=7.50.0
  23. Affected versionversion=7.50.1 <=7.50.1
  24. Affected versionversion=7.50.2 <=7.50.2
  25. Affected versionversion=7.50.3 <=7.50.3
  26. Affected versionversion=7.51.0 <=7.51.0
  27. Affected versionversion=7.52.0 <=7.52.0
  28. Affected versionversion=7.52.1 <=7.52.1
  29. Affected versionversion=7.53.0 <=7.53.0
  30. Affected versionversion=7.53.1 <=7.53.1
  31. Affected versionversion=7.54.0 <=7.54.0
  32. Affected versionversion=7.54.1 <=7.54.1
  33. Affected versionversion=7.55.0 <=7.55.0
  34. Affected versionversion=7.55.1 <=7.55.1
  35. Affected versionversion=7.56.0 <=7.56.0
  36. Affected versionversion=7.56.1 <=7.56.1
  37. Affected versionversion=7.57.0 <=7.57.0
  38. Affected versionversion=7.58.0 <=7.58.0
  39. Affected versionversion=7.59.0 <=7.59.0
  40. Affected versionversion=7.60.0 <=7.60.0
  41. Affected versionversion=7.61.0 <=7.61.0
  42. Affected versionversion=7.61.1 <=7.61.1
  43. Affected versionversion=7.62.0 <=7.62.0
  44. Affected versionversion=7.63.0 <=7.63.0
  45. Affected versionversion=7.64.0 <=7.64.0
  46. Affected versionversion=7.64.1 <=7.64.1
  47. Affected versionversion=7.65.0 <=7.65.0
  48. Affected versionversion=7.65.1 <=7.65.1
  49. Affected versionversion=7.65.2 <=7.65.2
  50. Affected versionversion=7.65.3 <=7.65.3
  51. Affected versionversion=7.66.0 <=7.66.0
  52. Affected versionversion=7.67.0 <=7.67.0
  53. Affected versionversion=7.68.0 <=7.68.0
  54. Affected versionversion=7.69.0 <=7.69.0
  55. Affected versionversion=7.69.1 <=7.69.1
  56. Affected versionversion=7.70.0 <=7.70.0
  57. Affected versionversion=7.71.0 <=7.71.0
  58. Affected versionversion=7.71.1 <=7.71.1
  59. Affected versionversion=7.72.0 <=7.72.0
  60. Affected versionversion=7.73.0 <=7.73.0
  61. Affected versionversion=7.74.0 <=7.74.0
  62. Affected versionversion=7.75.0 <=7.75.0
  63. Affected versionversion=7.76.0 <=7.76.0
  64. Affected versionversion=7.76.1 <=7.76.1
  65. Affected versionversion=7.77.0 <=7.77.0
  66. Affected versionversion=7.78.0 <=7.78.0
  67. Affected versionversion=7.79.0 <=7.79.0
  68. Affected versionversion=7.79.1 <=7.79.1
  69. Affected versionversion=7.80.0 <=7.80.0
  70. Affected versionversion=7.81.0 <=7.81.0
  71. Affected versionversion=7.82.0 <=7.82.0
  72. Affected versionversion=7.83.0 <=7.83.0
  73. Affected versionversion=7.83.1 <=7.83.1
  74. Affected versionversion=7.84.0 <=7.84.0
  75. Affected versionversion=7.85.0 <=7.85.0
  76. Affected versionversion=7.86.0 <=7.86.0
  77. Affected versionversion=7.87.0 <=7.87.0
  78. Affected versionversion=7.88.0 <=7.88.0
  79. Affected versionversion=7.88.1 <=7.88.1
  80. Affected versionversion=8.0.0 <=8.0.0
  81. Affected versionversion=8.0.1 <=8.0.1
  82. Affected versionversion=8.10.0 <=8.10.0
  83. Affected versionversion=8.10.1 <=8.10.1
  84. Affected versionversion=8.1.0 <=8.1.0
  85. Affected versionversion=8.11.0 <=8.11.0
  86. Affected versionversion=8.11.1 <=8.11.1
  87. Affected versionversion=8.1.1 <=8.1.1
  88. Affected versionversion=8.12.0 <=8.12.0
  89. Affected versionversion=8.12.1 <=8.12.1
  90. Affected versionversion=8.1.2 <=8.1.2
  91. Affected versionversion=8.13.0 <=8.13.0
  92. Affected versionversion=8.14.0 <=8.14.0
  93. Affected versionversion=8.14.1 <=8.14.1
  94. Affected versionversion=8.15.0 <=8.15.0
  95. Affected versionversion=8.16.0 <=8.16.0
  96. Affected versionversion=8.17.0 <=8.17.0
  97. Affected versionversion=8.18.0 <=8.18.0
  98. Affected versionversion=8.2.0 <=8.2.0
  99. Affected versionversion=8.2.1 <=8.2.1
  100. Affected versionversion=8.3.0 <=8.3.0
  101. Affected versionversion=8.4.0 <=8.4.0
  102. Affected versionversion=8.5.0 <=8.5.0
  103. Affected versionversion=8.6.0 <=8.6.0
  104. Affected versionversion=8.7.0 <=8.7.0
  105. Affected versionversion=8.7.1 <=8.7.1
  106. Affected versionversion=8.8.0 <=8.8.0
  107. Affected versionversion=8.9.0 <=8.9.0
  108. Affected versionversion=8.9.1 <=8.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=7.33.0 <=7.33.0; version=7.34.0 <=7.34.0; version=7.35.0 <=7.35.0; version=7.36.0 <=7.36.0; version=7.37.0 <=7.37.0; version=7.37.1 <=7.37.1; version=7.38.0 <=7.38.0; version=7.39.0 <=7.39.0; version=7.40.0 <=7.40.0; version=7.41.0 <=7.41.0; version=7.42.0 <=7.42.0; version=7.42.1 <=7.42.1; version=7.43.0 <=7.43.0; version=7.44.0 <=7.44.0; version=7.45.0 <=7.45.0; version=7.46.0 <=7.46.0; version=7.47.0 <=7.47.0; version=7.47.1 <=7.47.1; version=7.48.0 <=7.48.0; version=7.49.0 <=7.49.0; version=7.49.1 <=7.49.1; version=7.50.0 <=7.50.0; version=7.50.1 <=7.50.1; version=7.50.2 <=7.50.2; version=7.50.3 <=7.50.3; version=7.51.0 <=7.51.0; version=7.52.0 <=7.52.0; version=7.52.1 <=7.52.1; version=7.53.0 <=7.53.0; version=7.53.1 <=7.53.1; version=7.54.0 <=7.54.0; version=7.54.1 <=7.54.1; version=7.55.0 <=7.55.0; version=7.55.1 <=7.55.1; version=7.56.0 <=7.56.0; version=7.56.1 <=7.56.1; version=7.57.0 <=7.57.0; version=7.58.0 <=7.58.0; version=7.59.0 <=7.59.0; version=7.60.0 <=7.60.0; version=7.61.0 <=7.61.0; version=7.61.1 <=7.61.1; version=7.62.0 <=7.62.0; version=7.63.0 <=7.63.0; version=7.64.0 <=7.64.0; version=7.64.1 <=7.64.1; version=7.65.0 <=7.65.0; version=7.65.1 <=7.65.1; version=7.65.2 <=7.65.2; version=7.65.3 <=7.65.3; version=7.66.0 <=7.66.0; version=7.67.0 <=7.67.0; version=7.68.0 <=7.68.0; version=7.69.0 <=7.69.0; version=7.69.1 <=7.69.1; version=7.70.0 <=7.70.0; version=7.71.0 <=7.71.0; version=7.71.1 <=7.71.1; version=7.72.0 <=7.72.0; version=7.73.0 <=7.73.0; version=7.74.0 <=7.74.0; version=7.75.0 <=7.75.0; version=7.76.0 <=7.76.0; version=7.76.1 <=7.76.1; version=7.77.0 <=7.77.0; version=7.78.0 <=7.78.0; version=7.79.0 <=7.79.0; version=7.79.1 <=7.79.1; version=7.80.0 <=7.80.0; version=7.81.0 <=7.81.0; version=7.82.0 <=7.82.0; version=7.83.0 <=7.83.0; version=7.83.1 <=7.83.1; version=7.84.0 <=7.84.0; version=7.85.0 <=7.85.0; version=7.86.0 <=7.86.0; version=7.87.0 <=7.87.0; version=7.88.0 <=7.88.0; version=7.88.1 <=7.88.1; version=8.0.0 <=8.0.0; version=8.0.1 <=8.0.1; version=8.10.0 <=8.10.0; version=8.10.1 <=8.10.1; version=8.1.0 <=8.1.0; version=8.11.0 <=8.11.0; version=8.11.1 <=8.11.1; version=8.1.1 <=8.1.1; version=8.12.0 <=8.12.0; version=8.12.1 <=8.12.1; version=8.1.2 <=8.1.2; version=8.13.0 <=8.13.0; version=8.14.0 <=8.14.0; version=8.14.1 <=8.14.1; version=8.15.0 <=8.15.0; version=8.16.0 <=8.16.0; version=8.17.0 <=8.17.0; version=8.18.0 <=8.18.0; version=8.2.0 <=8.2.0; version=8.2.1 <=8.2.1; version=8.3.0 <=8.3.0; version=8.4.0 <=8.4.0; version=8.5.0 <=8.5.0; version=8.6.0 <=8.6.0; version=8.7.0 <=8.7.0; version=8.7.1 <=8.7.1; version=8.8.0 <=8.8.0; version=8.9.0 <=8.9.0; version=8.9.1 <=8.9.1

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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