RHSA-2026:93454HighCVSS 8.1

Red Hat Security Advisory: curl security update

Published
November 2, 2026
Last Modified
November 2, 2026

🔗 CVE IDs covered (9)

CVE-2026-8286 →CVE-2026-8458 →CVE-2026-8927 →CVE-2026-9547 →CVE-2026-11856 →CVE-2026-1965 →CVE-2026-3783 →CVE-2026-8924 →CVE-2026-8932 →

📋 Description

CVE-2026-1965 — curl: curl: Authentication bypass due to incorrect connection reuse with Negotiate authentication CVE-2026-3783 — curl: curl: Information disclosure via OAuth2 bearer token leakage during HTTP(S) redirect CVE-2026-8286 — curl: curl: Insecure connection establishment due to TLS configuration mismatch CVE-2026-8458 — curl: libcurl: Unauthorized connection reuse due to a logical error CVE-2026-8924 — curl: curl: Cookie injection via malicious HTTP server using super cookies CVE-2026-8927 — curl: Information disclosure due to uncleared proxy authentication state CVE-2026-8932 — libcurl: libcurl: Security feature bypass due to improper mTLS connection reuse CVE-2026-9547 — curl: curl: Man-in-the-middle attack via SSH host key bypass CVE-2026-11856 — curl: curl: Information disclosure via incorrect Digest authentication header reuse

🎯 Affected products76

  • Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-0:7.76.1-31.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-0:7.76.1-31.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-0:7.76.1-31.el9_6.4.s390x as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-0:7.76.1-31.el9_6.4.src as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-0:7.76.1-31.el9_6.4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.i686 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.i686 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.s390x as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debuginfo-0:7.76.1-31.el9_6.4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.i686 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.i686 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.s390x as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • curl-debugsource-0:7.76.1-31.el9_6.4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-minimal-0:7.76.1-31.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-minimal-0:7.76.1-31.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • curl-minimal-0:7.76.1-31.el9_6.4.s390x as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6)
  • +46 more not shown

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Workaround: To prevent the leakage of OAuth2 bearer tokens, ensure that `.netrc` files are carefully managed. Avoid configuring `.netrc` entries for untrusted or unknown hostnames, particularly when `curl` is used with OAuth2 bearer tokens and is configured to follow redirects. Regularly review and restrict the scope of credentials stored in `.netrc` files to only explicitly trusted destinations. Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Workaround: Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve Workaround: To mitigate this issue, applications utilizing libcurl should avoid reusing handles when switching between different proxy configurations. This operational control prevents the unintended leakage of `Proxy-Authorization` headers to incorrect proxies. Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0

🔗 References (12)