CVE-2024-9681Network attack vector

HTTP downgrade or interruption via parent cache overwrite

Published Nov 6, 2024 · Updated Nov 3, 2025

Incorrect HSTS cache handling in curl 7.74.0 through 8.10.1 allows remote attackers to alter parent-domain upgrade timing via a subdomain. In lib/hsts.c, Curl_hsts returned the first matching includeSubDomains tail, and hsts_add reused that entry without requiring a full host match. Triggering requires enabled HSTS, prepopulated entries for a parent and subdomain, insecure HTTP transfers to both, and a crafted Strict-Transport-Security response; the result is premature cleartext use or failed access.

CVSS severity6.5
Medium
EPSS probability1.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect HSTS cache handling in curl 7.74.0 through 8.10.1 allows remote attackers to alter parent-domain upgrade timing via a subdomain. In lib/hsts.c, Curl_hsts returned the first matching includeSubDomains tail, and hsts_add reused that entry without requiring a full host match. Triggering requires enabled HSTS, prepopulated entries for a parent and subdomain, insecure HTTP transfers to both, and a crafted Strict-Transport-Security response; the result is premature cleartext use or failed access.

The record

CVE
CVE-2024-9681
Published
Nov 6, 2024
Updated
Nov 3, 2025
Vendor
curl
Product
curl
Classifications
CWE-1025
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 6, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=7.74.0 <=7.74.0
  2. Affected versionversion=7.74.0 <=8.10.1
  3. Affected versionversion=7.75.0 <=7.75.0
  4. Affected versionversion=7.76.0 <=7.76.0
  5. Affected versionversion=7.76.1 <=7.76.1
  6. Affected versionversion=7.77.0 <=7.77.0
  7. Affected versionversion=7.78.0 <=7.78.0
  8. Affected versionversion=7.79.0 <=7.79.0
  9. Affected versionversion=7.79.1 <=7.79.1
  10. Affected versionversion=7.80.0 <=7.80.0
  11. Affected versionversion=7.81.0 <=7.81.0
  12. Affected versionversion=7.82.0 <=7.82.0
  13. Affected versionversion=7.83.0 <=7.83.0
  14. Affected versionversion=7.83.1 <=7.83.1
  15. Affected versionversion=7.84.0 <=7.84.0
  16. Affected versionversion=7.85.0 <=7.85.0
  17. Affected versionversion=7.86.0 <=7.86.0
  18. Affected versionversion=7.87.0 <=7.87.0
  19. Affected versionversion=7.88.0 <=7.88.0
  20. Affected versionversion=7.88.1 <=7.88.1
  21. Affected versionversion=8.0.0 <=8.0.0
  22. Affected versionversion=8.0.1 <=8.0.1
  23. Affected versionversion=8.10.0 <=8.10.0
  24. Affected versionversion=8.10.1 <=8.10.1
  25. Affected versionversion=8.1.0 <=8.1.0
  26. Affected versionversion=8.1.1 <=8.1.1
  27. Affected versionversion=8.1.2 <=8.1.2
  28. Affected versionversion=8.2.0 <=8.2.0
  29. Affected versionversion=8.2.1 <=8.2.1
  30. Affected versionversion=8.3.0 <=8.3.0
  31. Affected versionversion=8.4.0 <=8.4.0
  32. Affected versionversion=8.5.0 <=8.5.0
  33. Affected versionversion=8.6.0 <=8.6.0
  34. Affected versionversion=8.7.0 <=8.7.0
  35. Affected versionversion=8.7.1 <=8.7.1
  36. Affected versionversion=8.8.0 <=8.8.0
  37. Affected versionversion=8.9.0 <=8.9.0
  38. Affected versionversion=8.9.1 <=8.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=7.74.0 <=7.74.0; version=7.74.0 <=8.10.1; 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=8.1.1 <=8.1.1; version=8.1.2 <=8.1.2; 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

6.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L
5.9CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/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 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-1025Comparison Using Wrong Factors

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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