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MEDIUM

CVE-2024-9681

CVSS v3

6.5

MEDIUM

EPSS Score

2.0 %

exploit probability, as of 2026-10-18

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2024-9681 Red Hat Product Security8 known affected

    curl: HSTS subdomain overwrites parent cache entry

    curl as a component of Red Hat Enterprise Linux 9 · curl-minimal as a component of Red Hat Enterprise Linux 9 · curl.src as a component of Red Hat Enterprise Linux 9

  • ICSA-26-043-06 CISA16 known affected

    Siemens SINEC OS

    RUGGEDCOM RST2428P (6GK6242-6PA00) · SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family · SCALANCE XCH328 (6GK5328-4TS01-2EC2)

  • SSA-089022 Siemens ProductCERT16 known affected

    SSA-089022: Multiple Vulnerabilities in Third-Party Components in SINEC OS before V3.3

    RUGGEDCOM RST2428P (6GK6242-6PA00) · SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family · SCALANCE XCH328 (6GK5328-4TS01-2EC2)

  • ICSA-25-226-07 CISA3 known affected

    Siemens Third-Party Components in SINEC OS

    RUGGEDCOM RST2428P (6GK6242-6PA00) · SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family · SCALANCE XCM-/XRM-/XCH-/XRH-300 family

  • SSA-355557 Siemens ProductCERT3 known affected

    SSA-355557: Multiple Vulnerabilities in Third-Party Components in SINEC OS before V3.2

    RUGGEDCOM RST2428P (6GK6242-6PA00) · SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family · SCALANCE XCM-/XRM-/XCH-/XRH-300 family

Full record on NVD

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.

Technical details

Published
2024-11-06

Frequently asked questions

What is CVE-2024-9681?

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.

Is CVE-2024-9681 actively exploited?

Active exploitation of CVE-2024-9681 has not been confirmed. Its EPSS score was 2.0% on 2026-10-18, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2024-9681?

CVE-2024-9681 has a CVSS v3 base score of 6.5 (MEDIUM severity).

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