Bug 2553428 - CVE-2026-9545 rust: libcurl: Information disclosure via cached SSL session and early data [fedora-all]
Summary: CVE-2026-9545 rust: libcurl: Information disclosure via cached SSL session an...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: rust
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Rust SIG
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["9886f3a2-7f7e-40f5-b367-3...
Depends On:
Blocks: CVE-2026-9545
TreeView+ depends on / blocked
 
Reported: 2026-10-15 12:52 UTC by Avinash Hanwate
Modified: 2026-10-15 18:59 UTC (History)
6 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2026-10-15 18:59:36 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Avinash Hanwate 2026-10-15 12:52:20 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

In this scenario, libcurl first uses a proper HTTP/3 server for the initial
transfers, and when it makes a second transfer to the same site it has been
replaced by the attacker's impostor machine - without a valid certificate.

When libcurl returns to the hostname the second time with a cached SSL session
(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the
`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might
send off the second request's bytes on that new connection *before* enforcing
the certificate verification failure. Potentially leaking sensitive
information.

Comment 1 Josh Stone 2026-10-15 18:59:36 UTC
The bundled `curl` sources (via the Rust `curl-sys` crate) are wholly removed during the `%prep` phase to be sure we don't use them. Instead, we use the system `curl` library, so any CVE fixes only need to be made in that component on its own.


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