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Medium ALSA-2026:80512 5 CVEs

Moderate: curl security update

Published Oct 12, 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: Proxy credential disclosure via redirects to unauthenticated proxies (CVE-2026-6253)
* curl: libcurl: Authentication bypass due to incorrect HTTP Negotiate connection reuse (CVE-2026-5545)
* curl: libcurl: Credential leak via reused proxy connection during HTTP redirects (CVE-2026-6429)
* curl: libcurl: Information disclosure via incorrect Proxy-Authorization header reuse (CVE-2026-7168)
* libcurl: libcurl: Use-after-free vulnerability leading to Denial of Service (CVE-2026-10536)

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 4

ReleasePackageFixed in
AlmaLinux · 10 curl 8.12.1-4.el10_2.7
AlmaLinux · 10 libcurl 8.12.1-4.el10_2.7
AlmaLinux · 10 libcurl-devel 8.12.1-4.el10_2.7
AlmaLinux · 10 libcurl-minimal 8.12.1-4.el10_2.7

Vulnerabilities 5

  • Critical 9.8
    CVE-2026-10536

    HTTP/2 stream-dependency tree UAF

    A use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stream-dependency tree via `CURLOPT_STREAM_DEPENDS` or `CURLOPT_STREAM_DEPENDS_E`, subsequently invokes `curl_easy_reset()`, and finally terminates the handle with `curl…

    curl curl curl curl Debian Ubuntu Azure Linux Alpine
  • Medium 6.5
    CVE-2026-5545

    wrong reuse of HTTP Negotiate connection

    libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can re…

    curl curl curl curl Debian Ubuntu Azure Linux Alpine
  • Medium 5.9
    CVE-2026-6253

    proxy credentials leak over redirect-to proxy

    curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the se…

    curl curl curl curl Debian Ubuntu Azure Linux Alpine
  • Medium 5.3
    CVE-2026-6429

    netrc credential leak with reused proxy connection

    When asked to both use a `.netrc` file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances.

    curl curl curl curl Debian Ubuntu Azure Linux Alpine
  • Medium 5.3
    CVE-2026-7168

    cross-proxy Digest auth state leak

    Successfully using libcurl to do a transfer over a specific HTTP proxy (`proxyA`) with **Digest** authentication and then changing the proxy host to a second one (`proxyB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Pro…

    curl curl curl curl Debian Ubuntu Azure Linux Alpine

References

  • report
    https://access.redhat.com/security/cve/CVE-2026-10536
  • report
    https://access.redhat.com/security/cve/CVE-2026-5545
  • report
    https://access.redhat.com/security/cve/CVE-2026-6253
  • report
    https://access.redhat.com/security/cve/CVE-2026-6429
  • report
    https://access.redhat.com/security/cve/CVE-2026-7168
  • report
    https://bugzilla.redhat.com/2461202
  • report
    https://bugzilla.redhat.com/2461204
  • report
    https://bugzilla.redhat.com/2461205
  • report
    https://bugzilla.redhat.com/2476979
  • report
    https://bugzilla.redhat.com/2496766
  • advisory
    https://errata.almalinux.org/10/ALSA-2026-80512.html