CVE-2026-80231Network attack vector

HTTPS trust-policy bypass via mismatched connection reuse

Published Sep 6, 2026 · Updated Sep 8, 2026

Improper HTTPS connection reuse in curl 7.71.0 through 8.21.0 allows remote attackers to cause use of the wrong CA trust setting. The match_ssl_primary_config function omits native_ca_store when comparing TLS configurations, so a same-host connection created under one setting can satisfy a later transfer using the other. Exposure is limited to Windows and macOS and requires successive same-host transfers with different native-CA choices; the later transfer inherits the earlier connection's trust context.

CVSS severity2.1
Low
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper HTTPS connection reuse in curl 7.71.0 through 8.21.0 allows remote attackers to cause use of the wrong CA trust setting. The match_ssl_primary_config function omits native_ca_store when comparing TLS configurations, so a same-host connection created under one setting can satisfy a later transfer using the other. Exposure is limited to Windows and macOS and requires successive same-host transfers with different native-CA choices; the later transfer inherits the earlier connection's trust context.

The record

CVE
CVE-2026-80231
Published
Sep 6, 2026
Updated
Sep 8, 2026
Vendor
curl
Product
curl
Classifications
CWE-488
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 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=8.20.0 <=8.20.0
  44. Affected versionversion=8.2.0 <=8.2.0
  45. Affected versionversion=8.21.0 <=8.21.0
  46. Affected versionversion=8.2.1 <=8.2.1
  47. Affected versionversion=8.3.0 <=8.3.0
  48. Affected versionversion=8.4.0 <=8.4.0
  49. Affected versionversion=8.5.0 <=8.5.0
  50. Affected versionversion=8.6.0 <=8.6.0
  51. Affected versionversion=8.7.0 <=8.7.0
  52. Affected versionversion=8.7.1 <=8.7.1
  53. Affected versionversion=8.8.0 <=8.8.0
  54. Affected versionversion=8.9.0 <=8.9.0
  55. 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=8.20.0 <=8.20.0; version=8.2.0 <=8.2.0; version=8.21.0 <=8.21.0; 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

2.1SUSECVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
4.8Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1SUSECVSS:3.1/AV:N/AC:H/PR:N/UI:R/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-488Exposure of Data Element to Wrong Session

Public exploit references

No public exploit references are available in this record.

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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