CVE-2026-11856Public exploitNetwork attack vector

Authentication replay via cross-origin Digest state reuse

Published Jul 3, 2026 · Updated Jul 3, 2026

Information disclosure in libcurl 7.10.6 through 8.20.0 allows remote attackers to capture Digest authentication state across HTTP origins. Curl_output_digest reuses handle-scoped Digest state without checking whether the destination origin or credentials changed, so it sends hostA's Authorization header to hostB. Exploitation requires a successful Digest-authenticated request followed by reuse of the same easy handle for an attacker-controlled origin; the header enables replay of only that request path and does not reveal the password or hostA address.

CVSS severity9.8
Critical
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in libcurl 7.10.6 through 8.20.0 allows remote attackers to capture Digest authentication state across HTTP origins. Curl_output_digest reuses handle-scoped Digest state without checking whether the destination origin or credentials changed, so it sends hostA's Authorization header to hostB. Exploitation requires a successful Digest-authenticated request followed by reuse of the same easy handle for an attacker-controlled origin; the header enables replay of only that request path and does not reveal the password or hostA address.

The record

CVE
CVE-2026-11856
Published
Jul 3, 2026
Updated
Jul 3, 2026
Vendor
curl
Product
curl
Classifications
CWE-294, T1550
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=7.10.6 <=7.10.6
  2. Affected versionversion=7.10.7 <=7.10.7
  3. Affected versionversion=7.10.8 <=7.10.8
  4. Affected versionversion=7.11.0 <=7.11.0
  5. Affected versionversion=7.11.1 <=7.11.1
  6. Affected versionversion=7.11.2 <=7.11.2
  7. Affected versionversion=7.12.0 <=7.12.0
  8. Affected versionversion=7.12.1 <=7.12.1
  9. Affected versionversion=7.12.2 <=7.12.2
  10. Affected versionversion=7.12.3 <=7.12.3
  11. Affected versionversion=7.13.0 <=7.13.0
  12. Affected versionversion=7.13.1 <=7.13.1
  13. Affected versionversion=7.13.2 <=7.13.2
  14. Affected versionversion=7.14.0 <=7.14.0
  15. Affected versionversion=7.14.1 <=7.14.1
  16. Affected versionversion=7.15.0 <=7.15.0
  17. Affected versionversion=7.15.1 <=7.15.1
  18. Affected versionversion=7.15.2 <=7.15.2
  19. Affected versionversion=7.15.3 <=7.15.3
  20. Affected versionversion=7.15.4 <=7.15.4
  21. Affected versionversion=7.15.5 <=7.15.5
  22. Affected versionversion=7.16.0 <=7.16.0
  23. Affected versionversion=7.16.1 <=7.16.1
  24. Affected versionversion=7.16.2 <=7.16.2
  25. Affected versionversion=7.16.3 <=7.16.3
  26. Affected versionversion=7.16.4 <=7.16.4
  27. Affected versionversion=7.17.0 <=7.17.0
  28. Affected versionversion=7.17.1 <=7.17.1
  29. Affected versionversion=7.18.0 <=7.18.0
  30. Affected versionversion=7.18.1 <=7.18.1
  31. Affected versionversion=7.18.2 <=7.18.2
  32. Affected versionversion=7.19.0 <=7.19.0
  33. Affected versionversion=7.19.1 <=7.19.1
  34. Affected versionversion=7.19.2 <=7.19.2
  35. Affected versionversion=7.19.3 <=7.19.3
  36. Affected versionversion=7.19.4 <=7.19.4
  37. Affected versionversion=7.19.5 <=7.19.5
  38. Affected versionversion=7.19.6 <=7.19.6
  39. Affected versionversion=7.19.7 <=7.19.7
  40. Affected versionversion=7.20.0 <=7.20.0
  41. Affected versionversion=7.20.1 <=7.20.1
  42. Affected versionversion=7.21.0 <=7.21.0
  43. Affected versionversion=7.21.1 <=7.21.1
  44. Affected versionversion=7.21.2 <=7.21.2
  45. Affected versionversion=7.21.3 <=7.21.3
  46. Affected versionversion=7.21.4 <=7.21.4
  47. Affected versionversion=7.21.5 <=7.21.5
  48. Affected versionversion=7.21.6 <=7.21.6
  49. Affected versionversion=7.21.7 <=7.21.7
  50. Affected versionversion=7.22.0 <=7.22.0
  51. Affected versionversion=7.23.0 <=7.23.0
  52. Affected versionversion=7.23.1 <=7.23.1
  53. Affected versionversion=7.24.0 <=7.24.0
  54. Affected versionversion=7.25.0 <=7.25.0
  55. Affected versionversion=7.26.0 <=7.26.0
  56. Affected versionversion=7.27.0 <=7.27.0
  57. Affected versionversion=7.28.0 <=7.28.0
  58. Affected versionversion=7.28.1 <=7.28.1
  59. Affected versionversion=7.29.0 <=7.29.0
  60. Affected versionversion=7.30.0 <=7.30.0
  61. Affected versionversion=7.31.0 <=7.31.0
  62. Affected versionversion=7.32.0 <=7.32.0
  63. Affected versionversion=7.33.0 <=7.33.0
  64. Affected versionversion=7.34.0 <=7.34.0
  65. Affected versionversion=7.35.0 <=7.35.0
  66. Affected versionversion=7.36.0 <=7.36.0
  67. Affected versionversion=7.37.0 <=7.37.0
  68. Affected versionversion=7.37.1 <=7.37.1
  69. Affected versionversion=7.38.0 <=7.38.0
  70. Affected versionversion=7.39.0 <=7.39.0
  71. Affected versionversion=7.40.0 <=7.40.0
  72. Affected versionversion=7.41.0 <=7.41.0
  73. Affected versionversion=7.42.0 <=7.42.0
  74. Affected versionversion=7.42.1 <=7.42.1
  75. Affected versionversion=7.43.0 <=7.43.0
  76. Affected versionversion=7.44.0 <=7.44.0
  77. Affected versionversion=7.45.0 <=7.45.0
  78. Affected versionversion=7.46.0 <=7.46.0
  79. Affected versionversion=7.47.0 <=7.47.0
  80. Affected versionversion=7.47.1 <=7.47.1
  81. Affected versionversion=7.48.0 <=7.48.0
  82. Affected versionversion=7.49.0 <=7.49.0
  83. Affected versionversion=7.49.1 <=7.49.1
  84. Affected versionversion=7.50.0 <=7.50.0
  85. Affected versionversion=7.50.1 <=7.50.1
  86. Affected versionversion=7.50.2 <=7.50.2
  87. Affected versionversion=7.50.3 <=7.50.3
  88. Affected versionversion=7.51.0 <=7.51.0
  89. Affected versionversion=7.52.0 <=7.52.0
  90. Affected versionversion=7.52.1 <=7.52.1
  91. Affected versionversion=7.53.0 <=7.53.0
  92. Affected versionversion=7.53.1 <=7.53.1
  93. Affected versionversion=7.54.0 <=7.54.0
  94. Affected versionversion=7.54.1 <=7.54.1
  95. Affected versionversion=7.55.0 <=7.55.0
  96. Affected versionversion=7.55.1 <=7.55.1
  97. Affected versionversion=7.56.0 <=7.56.0
  98. Affected versionversion=7.56.1 <=7.56.1
  99. Affected versionversion=7.57.0 <=7.57.0
  100. Affected versionversion=7.58.0 <=7.58.0
  101. Affected versionversion=7.59.0 <=7.59.0
  102. Affected versionversion=7.60.0 <=7.60.0
  103. Affected versionversion=7.61.0 <=7.61.0
  104. Affected versionversion=7.61.1 <=7.61.1
  105. Affected versionversion=7.62.0 <=7.62.0
  106. Affected versionversion=7.63.0 <=7.63.0
  107. Affected versionversion=7.64.0 <=7.64.0
  108. Affected versionversion=7.64.1 <=7.64.1
  109. Affected versionversion=7.65.0 <=7.65.0
  110. Affected versionversion=7.65.1 <=7.65.1
  111. Affected versionversion=7.65.2 <=7.65.2
  112. Affected versionversion=7.65.3 <=7.65.3
  113. Affected versionversion=7.66.0 <=7.66.0
  114. Affected versionversion=7.67.0 <=7.67.0
  115. Affected versionversion=7.68.0 <=7.68.0
  116. Affected versionversion=7.69.0 <=7.69.0
  117. Affected versionversion=7.69.1 <=7.69.1
  118. Affected versionversion=7.70.0 <=7.70.0
  119. Affected versionversion=7.71.0 <=7.71.0
  120. Affected versionversion=7.71.1 <=7.71.1
  121. Affected versionversion=7.72.0 <=7.72.0
  122. Affected versionversion=7.73.0 <=7.73.0
  123. Affected versionversion=7.74.0 <=7.74.0
  124. Affected versionversion=7.75.0 <=7.75.0
  125. Affected versionversion=7.76.0 <=7.76.0
  126. Affected versionversion=7.76.1 <=7.76.1
  127. Affected versionversion=7.77.0 <=7.77.0
  128. Affected versionversion=7.78.0 <=7.78.0
  129. Affected versionversion=7.79.0 <=7.79.0
  130. Affected versionversion=7.79.1 <=7.79.1
  131. Affected versionversion=7.80.0 <=7.80.0
  132. Affected versionversion=7.81.0 <=7.81.0
  133. Affected versionversion=7.82.0 <=7.82.0
  134. Affected versionversion=7.83.0 <=7.83.0
  135. Affected versionversion=7.83.1 <=7.83.1
  136. Affected versionversion=7.84.0 <=7.84.0
  137. Affected versionversion=7.85.0 <=7.85.0
  138. Affected versionversion=7.86.0 <=7.86.0
  139. Affected versionversion=7.87.0 <=7.87.0
  140. Affected versionversion=7.88.0 <=7.88.0
  141. Affected versionversion=7.88.1 <=7.88.1
  142. Affected versionversion=8.0.0 <=8.0.0
  143. Affected versionversion=8.0.1 <=8.0.1
  144. Affected versionversion=8.10.0 <=8.10.0
  145. Affected versionversion=8.10.1 <=8.10.1
  146. Affected versionversion=8.1.0 <=8.1.0
  147. Affected versionversion=8.11.0 <=8.11.0
  148. Affected versionversion=8.11.1 <=8.11.1
  149. Affected versionversion=8.1.1 <=8.1.1
  150. Affected versionversion=8.12.0 <=8.12.0
  151. Affected versionversion=8.12.1 <=8.12.1
  152. Affected versionversion=8.1.2 <=8.1.2
  153. Affected versionversion=8.13.0 <=8.13.0
  154. Affected versionversion=8.14.0 <=8.14.0
  155. Affected versionversion=8.14.1 <=8.14.1
  156. Affected versionversion=8.15.0 <=8.15.0
  157. Affected versionversion=8.16.0 <=8.16.0
  158. Affected versionversion=8.17.0 <=8.17.0
  159. Affected versionversion=8.18.0 <=8.18.0
  160. Affected versionversion=8.19.0 <=8.19.0
  161. Affected versionversion=8.20.0 <=8.20.0
  162. Affected versionversion=8.2.0 <=8.2.0
  163. Affected versionversion=8.2.1 <=8.2.1
  164. Affected versionversion=8.3.0 <=8.3.0
  165. Affected versionversion=8.4.0 <=8.4.0
  166. Affected versionversion=8.5.0 <=8.5.0
  167. Affected versionversion=8.6.0 <=8.6.0
  168. Affected versionversion=8.7.0 <=8.7.0
  169. Affected versionversion=8.7.1 <=8.7.1
  170. Affected versionversion=8.8.0 <=8.8.0
  171. Affected versionversion=8.9.0 <=8.9.0
  172. Affected versionversion=8.9.1 <=8.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=7.10.6 <=7.10.6; version=7.10.7 <=7.10.7; version=7.10.8 <=7.10.8; version=7.11.0 <=7.11.0; version=7.11.1 <=7.11.1; version=7.11.2 <=7.11.2; version=7.12.0 <=7.12.0; version=7.12.1 <=7.12.1; version=7.12.2 <=7.12.2; version=7.12.3 <=7.12.3; version=7.13.0 <=7.13.0; version=7.13.1 <=7.13.1; version=7.13.2 <=7.13.2; version=7.14.0 <=7.14.0; version=7.14.1 <=7.14.1; version=7.15.0 <=7.15.0; version=7.15.1 <=7.15.1; version=7.15.2 <=7.15.2; version=7.15.3 <=7.15.3; version=7.15.4 <=7.15.4; version=7.15.5 <=7.15.5; version=7.16.0 <=7.16.0; version=7.16.1 <=7.16.1; version=7.16.2 <=7.16.2; version=7.16.3 <=7.16.3; version=7.16.4 <=7.16.4; version=7.17.0 <=7.17.0; version=7.17.1 <=7.17.1; version=7.18.0 <=7.18.0; version=7.18.1 <=7.18.1; version=7.18.2 <=7.18.2; version=7.19.0 <=7.19.0; version=7.19.1 <=7.19.1; version=7.19.2 <=7.19.2; version=7.19.3 <=7.19.3; version=7.19.4 <=7.19.4; version=7.19.5 <=7.19.5; version=7.19.6 <=7.19.6; version=7.19.7 <=7.19.7; version=7.20.0 <=7.20.0; version=7.20.1 <=7.20.1; version=7.21.0 <=7.21.0; version=7.21.1 <=7.21.1; version=7.21.2 <=7.21.2; version=7.21.3 <=7.21.3; version=7.21.4 <=7.21.4; version=7.21.5 <=7.21.5; version=7.21.6 <=7.21.6; version=7.21.7 <=7.21.7; version=7.22.0 <=7.22.0; version=7.23.0 <=7.23.0; version=7.23.1 <=7.23.1; version=7.24.0 <=7.24.0; version=7.25.0 <=7.25.0; version=7.26.0 <=7.26.0; version=7.27.0 <=7.27.0; version=7.28.0 <=7.28.0; version=7.28.1 <=7.28.1; version=7.29.0 <=7.29.0; version=7.30.0 <=7.30.0; version=7.31.0 <=7.31.0; version=7.32.0 <=7.32.0; version=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=8.19.0 <=8.19.0; version=8.20.0 <=8.20.0; 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

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T1550Use Alternate Authentication Material

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

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