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OpenAdvisories
High ALSA-2026:55439 4 CVEs

Important: curl security update

Published Aug 17, 2026 · Updated Oct 29, 2026

Ecosystem: AlmaLinux

Summary

The curl packages provide the libcurl library and the curl utility for downloading files from servers using various protocols, including HTTP, FTP, and LDAP.

Security Fix(es):

* curl: curl: Authentication bypass due to incorrect connection reuse with Negotiate authentication (CVE-2026-1965)
* curl: curl: Information disclosure via OAuth2 bearer token leakage during HTTP(S) redirect (CVE-2026-3783)
* curl: curl: Man-in-the-middle attack via SSH host key bypass (CVE-2026-9547)
* curl: curl: Insecure connection establishment due to TLS configuration mismatch (CVE-2026-8286)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Fixed packages 5

ReleasePackageFixed in
AlmaLinux · 9 curl 7.76.1-40.el9_8.5
AlmaLinux · 9 curl-minimal 7.76.1-40.el9_8.5
AlmaLinux · 9 libcurl 7.76.1-40.el9_8.5
AlmaLinux · 9 libcurl-devel 7.76.1-40.el9_8.5
AlmaLinux · 9 libcurl-minimal 7.76.1-40.el9_8.5

Vulnerabilities 4

  • High 8.1
    CVE-2026-8286

    wrong STARTTLS connection reuse

    A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

    curl curl curl curl Debian Ubuntu Azure Linux Alpine
  • High 7.4
    CVE-2026-9547

    SSH improper host validation

    When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match…

    curl curl curl curl Debian Ubuntu Alpine
  • Medium 6.5
    CVE-2026-1965

    bad reuse of HTTP Negotiate connection

    libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When …

    curl curl curl curl Debian Ubuntu Azure Linux Alpine
  • Medium 5.3
    CVE-2026-3783

    token leak with redirect and netrc

    When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect to a second URL, curl could leak that token to the second hostname under some circumstances. If the hostname that the first request is redirected to has informa…

    curl curl curl curl Debian Ubuntu Azure Linux Alpine

References

  • report
    https://access.redhat.com/security/cve/CVE-2026-1965
  • report
    https://access.redhat.com/security/cve/CVE-2026-3783
  • report
    https://access.redhat.com/security/cve/CVE-2026-8286
  • report
    https://access.redhat.com/security/cve/CVE-2026-9547
  • report
    https://bugzilla.redhat.com/2446448
  • report
    https://bugzilla.redhat.com/2446450
  • report
    https://bugzilla.redhat.com/2496758
  • report
    https://bugzilla.redhat.com/2496763
  • advisory
    https://errata.almalinux.org/9/ALSA-2026-55439.html