CVE-2026-8927Public exploitNetwork attack vector

Client impersonation via uncleared proxy Digest state

Published Jul 3, 2026 · Updated Jul 3, 2026

Authentication state disclosure in curl 7.12.0 through 8.20.0 allows remote attackers controlling a second proxy to obtain Digest auth state. The libcurl environment-proxy selection path reuses an easy handle without comparing the new proxy or clearing state.proxydigest, so Proxy-Authorization is sent to the second proxy. Exploitation requires sequential handle reuse, environment-variable proxy changes, and Digest proxy authentication; the second proxy can replay the state to impersonate the client to the first proxy, although the leaked request does not identify that proxy.

CVSS severity9.1
Critical
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication state disclosure in curl 7.12.0 through 8.20.0 allows remote attackers controlling a second proxy to obtain Digest auth state. The libcurl environment-proxy selection path reuses an easy handle without comparing the new proxy or clearing state.proxydigest, so Proxy-Authorization is sent to the second proxy. Exploitation requires sequential handle reuse, environment-variable proxy changes, and Digest proxy authentication; the second proxy can replay the state to impersonate the client to the first proxy, although the leaked request does not identify that proxy.

The record

CVE
CVE-2026-8927
Published
Jul 3, 2026
Updated
Jul 3, 2026
Vendor
curl
Product
curl
Classifications
CWE-294, T1557
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

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

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=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

9.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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-294Authentication Bypass by Capture-replay
T1557Adversary-in-the-Middle

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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