CVE-2024-9681HSTS subdomain overwrites parent cache entry

Description

When curl is asked to use HSTS, the expiry time for a subdomain might overwrite a parent domain's cache entry, making it end sooner or later than otherwise intended. This affects curl using applications that enable HSTS and use URLs with the insecure `HTTP://` scheme and perform transfers with hosts like `x.example.com` as well as `example.com` where the first host is a subdomain of the second host. (The HSTS cache either needs to have been populated manually or there needs to have been previous HTTPS accesses done as the cache needs to have entries for the domains involved to trigger this problem.) When `x.example.com` responds with `Strict-Transport-Security:` headers, this bug can make the subdomain's expiry timeout *bleed over* and get set for the parent domain `example.com` in curl's HSTS cache. The result of a triggered bug is that HTTP accesses to `example.com` get converted to HTTPS for a different period of time than what was asked for by the origin server. If `example.com` for example stops supporting HTTPS at its expiry time, curl might then fail to access `http://example.com` until the (wrongly set) timeout expires. This bug can also expire the parent's entry *earlier*, thus making curl inadvertently switch back to insecure HTTP earlier than otherwise intended.

Timeline

Scores

EPSS (exploitation in 30 days)

2.0% · top 19% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Affected products

• curl · curl

  • affected 8.10.1 – ≤ 8.10.1
  • affected 8.10.0 – ≤ 8.10.0
  • affected 8.9.1 – ≤ 8.9.1
  • affected 8.9.0 – ≤ 8.9.0
  • affected 8.8.0 – ≤ 8.8.0
  • affected 8.7.1 – ≤ 8.7.1
  • affected 8.7.0 – ≤ 8.7.0
  • affected 8.6.0 – ≤ 8.6.0
  • affected 8.5.0 – ≤ 8.5.0
  • affected 8.4.0 – ≤ 8.4.0
  • affected 8.3.0 – ≤ 8.3.0
  • affected 8.2.1 – ≤ 8.2.1
  • affected 8.2.0 – ≤ 8.2.0
  • affected 8.1.2 – ≤ 8.1.2
  • affected 8.1.1 – ≤ 8.1.1
  • affected 8.1.0 – ≤ 8.1.0
  • affected 8.0.1 – ≤ 8.0.1
  • affected 8.0.0 – ≤ 8.0.0
  • affected 7.88.1 – ≤ 7.88.1
  • affected 7.88.0 – ≤ 7.88.0
  • affected 7.87.0 – ≤ 7.87.0
  • affected 7.86.0 – ≤ 7.86.0
  • affected 7.85.0 – ≤ 7.85.0
  • affected 7.84.0 – ≤ 7.84.0
  • affected 7.83.1 – ≤ 7.83.1
  • affected 7.83.0 – ≤ 7.83.0
  • affected 7.82.0 – ≤ 7.82.0
  • affected 7.81.0 – ≤ 7.81.0
  • affected 7.80.0 – ≤ 7.80.0
  • affected 7.79.1 – ≤ 7.79.1
  • affected 7.79.0 – ≤ 7.79.0
  • affected 7.78.0 – ≤ 7.78.0
  • affected 7.77.0 – ≤ 7.77.0
  • affected 7.76.1 – ≤ 7.76.1
  • affected 7.76.0 – ≤ 7.76.0
  • affected 7.75.0 – ≤ 7.75.0
  • affected 7.74.0 – ≤ 7.74.0

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2024-50377 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2024-9681](https://cveledger.app/badge/CVE-2024-9681.svg)](https://cveledger.app/cve/CVE-2024-9681)

Record last updated 3 Nov 2025, 20:56 UTC.