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Vulnerabilities

Vulnerability · CVE-2026-5545

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.

Published May 13, 2026 · catalog updated Oct 18, 2026 · libcurl might in some

Check if you run it

No confirmed exploitation is on record for CVE-2026-5545. EPSS is 0.41%. Act only if a listed version of libcurl might in some is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (libcurl might in some).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.41%
Remediation
Advisory link
Affected products
Alpine:v3.21 curl · Alpine:v3.22 curl · Alpine:v3.23 curl · Alpine:v3.24 curl · cpe haxx/curl

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 reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. An application that first uses Negotiate authentication to a server with and then does another operation to the same server asking for any authentication method but for (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Alpine:v3.21 curl7.10.6 → 8.14.1-r3
  • Alpine:v3.22 curl7.10.6 → 8.14.1-r3
  • Alpine:v3.23 curl7.10.6 → 8.20.0-r0
  • Alpine:v3.24 curl7.10.6 → 8.20.0-r0
  • cpe haxx/curlversion unspecified

How to fix CVE-2026-5545

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-5545. EPSS is 0.41%. Act only if a listed version of libcurl might in some is installed.

Which versions are affected?

Compare what you have installed with 7.10.6 → 8.14.1-r3, 7.10.6 → 8.20.0-r0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-305; CWE-613: Insufficient Session Expiration. EPSS 0.41%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 13, 2026 · NIST NVD

    Detected

    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 reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code,

  2. Sep 15, 2026 · NIST NVD

    Updated

    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 reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code,

  3. Oct 18, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    curl fixed in 8.14.1-r3; curl fixed in 8.14.1-r3; curl fixed in 8.20.0-r0; curl fixed in 8.20.0-r0

  4. Oct 18, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    curl fixed in 8.14.1-r3

  5. Oct 18, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    curl fixed in 8.20.0-r0

  6. Oct 18, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code,

Sources

  • CVE.orgVulnerability recordCVE-2026-5545

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-5545

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-5545

    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 reuse an existing conn

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryALPINE-CVE-2026-5545
    osv.dev
  • Trivy Vulnerability DBPackage advisoryALPINE-CVE-2026-5545

    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 reuse an existing conne

    osv.dev

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.