CVE-2026-6276Public exploitNetwork attack vector

Cookie disclosure via reused easy-handle host state

Published May 13, 2026 · Updated May 13, 2026

Information disclosure in libcurl 7.71.0 through 8.19.0 allows context-dependent attackers to receive cookies via handle reuse. The cookie host remains in the easy handle's UrlState after a custom Host header is removed, so the next request selects cookies using the prior host. Exploitation requires an application to enable cookies, set a custom Host header, reuse the handle for another HTTP destination, and reach an attacker-controlled server.

CVSS severity7.5
High
EPSS probability0.29%
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 7.71.0 through 8.19.0 allows context-dependent attackers to receive cookies via handle reuse. The cookie host remains in the easy handle's UrlState after a custom Host header is removed, so the next request selects cookies using the prior host. Exploitation requires an application to enable cookies, set a custom Host header, reuse the handle for another HTTP destination, and reach an attacker-controlled server.

The record

CVE
CVE-2026-6276
Published
May 13, 2026
Updated
May 13, 2026
Vendor
curl
Product
curl
Classifications
CWE-319, CWE-346, T1539
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 13, 2026CVE publishedPublication date reported by the CVE source.
  2. May 13, 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=7.71.0 <=7.71.0
  2. Affected versionversion=7.71.1 <=7.71.1
  3. Affected versionversion=7.72.0 <=7.72.0
  4. Affected versionversion=7.73.0 <=7.73.0
  5. Affected versionversion=7.74.0 <=7.74.0
  6. Affected versionversion=7.75.0 <=7.75.0
  7. Affected versionversion=7.76.0 <=7.76.0
  8. Affected versionversion=7.76.1 <=7.76.1
  9. Affected versionversion=7.77.0 <=7.77.0
  10. Affected versionversion=7.78.0 <=7.78.0
  11. Affected versionversion=7.79.0 <=7.79.0
  12. Affected versionversion=7.79.1 <=7.79.1
  13. Affected versionversion=7.80.0 <=7.80.0
  14. Affected versionversion=7.81.0 <=7.81.0
  15. Affected versionversion=7.82.0 <=7.82.0
  16. Affected versionversion=7.83.0 <=7.83.0
  17. Affected versionversion=7.83.1 <=7.83.1
  18. Affected versionversion=7.84.0 <=7.84.0
  19. Affected versionversion=7.85.0 <=7.85.0
  20. Affected versionversion=7.86.0 <=7.86.0
  21. Affected versionversion=7.87.0 <=7.87.0
  22. Affected versionversion=7.88.0 <=7.88.0
  23. Affected versionversion=7.88.1 <=7.88.1
  24. Affected versionversion=8.0.0 <=8.0.0
  25. Affected versionversion=8.0.1 <=8.0.1
  26. Affected versionversion=8.10.0 <=8.10.0
  27. Affected versionversion=8.10.1 <=8.10.1
  28. Affected versionversion=8.1.0 <=8.1.0
  29. Affected versionversion=8.11.0 <=8.11.0
  30. Affected versionversion=8.11.1 <=8.11.1
  31. Affected versionversion=8.1.1 <=8.1.1
  32. Affected versionversion=8.12.0 <=8.12.0
  33. Affected versionversion=8.12.1 <=8.12.1
  34. Affected versionversion=8.1.2 <=8.1.2
  35. Affected versionversion=8.13.0 <=8.13.0
  36. Affected versionversion=8.14.0 <=8.14.0
  37. Affected versionversion=8.14.1 <=8.14.1
  38. Affected versionversion=8.15.0 <=8.15.0
  39. Affected versionversion=8.16.0 <=8.16.0
  40. Affected versionversion=8.17.0 <=8.17.0
  41. Affected versionversion=8.18.0 <=8.18.0
  42. Affected versionversion=8.19.0 <=8.19.0
  43. Affected versionversion=8.2.0 <=8.2.0
  44. Affected versionversion=8.2.1 <=8.2.1
  45. Affected versionversion=8.3.0 <=8.3.0
  46. Affected versionversion=8.4.0 <=8.4.0
  47. Affected versionversion=8.5.0 <=8.5.0
  48. Affected versionversion=8.6.0 <=8.6.0
  49. Affected versionversion=8.7.0 <=8.7.0
  50. Affected versionversion=8.7.1 <=8.7.1
  51. Affected versionversion=8.8.0 <=8.8.0
  52. Affected versionversion=8.9.0 <=8.9.0
  53. Affected versionversion=8.9.1 <=8.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=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=8.2.0 <=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

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.7Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
6.3SUSECVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.7SUSECVSS:3.1/AV:N/AC:H/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 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-319Cleartext Transmission of Sensitive Information
CWE-346Origin Validation Error
T1539Steal Web Session Cookie

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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