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curl vulnerabilities · Page 2

Vulnerabilities published for curl in the last 30 days: 9. Listed in the KEV catalogue: 0.

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Vulnerabilities: 50

  1. CVE-2026-11856

    Critical · CVSS 9.8EPSS 0.69%Fix available

    cross-origin Digest auth state leak

    Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

    • Update to 8.5.0-2ubuntu10.12
    Published Updated
  2. CVE-2026-10536

    Critical · CVSS 9.8EPSS 0.6%Fix available

    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_easy_cleanup()`. During this final cleanup phase, libcurl attempts to access and modify an internal structure that was already freed during the reset operation.

    • Update to 8.5.0-2ubuntu10.11
    Published Updated
  3. CVE-2026-7168

    Medium · CVSS 5.3EPSS 0.47%Fix available

    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 `Proxy-Authorization:` header field meant for `proxyA`, to `proxyB`.

    • Update to 8.5.0-2ubuntu10.9
    Published Updated
  4. CVE-2026-6276

    High · CVSS 7.5EPSS 0.29%Fix available

    stale custom cookie host causes cookie leak

    Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.

    • Update to 8.5.0-2ubuntu10.9
    Published Updated
  5. CVE-2026-6253

    Medium · CVSS 5.9EPSS 0.72%Fix available

    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 second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy

    • Update to 8.5.0-2ubuntu10.9
    Published Updated
  6. CVE-2026-5773

    High · CVSS 7.5EPSS 0.62%Fix available

    wrong reuse of SMB connection

    libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. 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 network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different "share" than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happ

    • Update to 8.5.0-2ubuntu10.9
    Published Updated
  7. CVE-2026-5545

    Medium · CVSS 6.5EPSS 0.41%Fix available

    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 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 `user1:passwo

    • Update to 8.5.0-2ubuntu10.9
    Published Updated
  8. CVE-2026-4873

    Medium · CVSS 5.9EPSS 0.33%Fix available

    connection reuse ignores TLS requirement

    A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.

    • Update to 8.5.0-2ubuntu10.9
    Published Updated
  9. CVE-2026-3783

    Medium · CVSS 5.3EPSS 0.47%Fix available

    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 information in the used .netrc file, with either of the `machine` or `default` keywords, curl would pass on the bearer token set for the first host also to the second one.

    • Update to 8.5.0-2ubuntu10.8
    Published Updated
  10. CVE-2026-1965

    Medium · CVSS 6.5EPSS 0.27%Fix available

    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 reusing a connection a range of criterion must first 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. One underlying reason being that Negotiate sometimes authenticates *connections* and not *requests*, contrary to how HTTP is design

    • Update to 8.5.0-2ubuntu10.8
    Published Updated
  11. CVE-2025-15079

    Medium · CVSS 5.3EPSS 0.55%Fix available

    libssh global known_hosts override

    When doing SSH-based transfers using either SCP or SFTP, and setting the known_hosts file, libcurl could still mistakenly accept connecting to hosts *not present* in the specified file if they were added as recognized in the libssh *global* known_hosts file.

    • Update to 8.5.0-2ubuntu10.7
    Published Updated
  12. CVE-2025-14819

    Medium · CVSS 5.3EPSS 0.76%Fix available

    OpenSSL partial chain store policy bypass

    When doing TLS related transfers with reused easy or multi handles and altering the `CURLSSLOPT_NO_PARTIALCHAIN` option, libcurl could accidentally reuse a CA store cached in memory for which the partial chain option was reversed. Contrary to the user's wishes and expectations. This could make libcurl find and accept a trust chain that it otherwise would not.

    • Update to 8.5.0-2ubuntu10.7
    Published Updated
  13. CVE-2025-14524

    Medium · CVSS 5.3EPSS 0.68%Fix available

    bearer token leak on cross-protocol redirect

    When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a cross-protocol redirect to a second URL that uses an IMAP, LDAP, POP3 or SMTP scheme, curl might wrongly pass on the bearer token to the new target host.

    • Update to 8.5.0-2ubuntu10.7
    Published Updated
  14. CVE-2025-14017

    Medium · CVSS 6.3EPSS 0.11%Fix available

    broken TLS options for threaded LDAPS

    When doing multi-threaded LDAPS transfers (LDAP over TLS) with libcurl, changing TLS options in one thread would inadvertently change them globally and therefore possibly also affect other concurrently setup transfers. Disabling certificate verification for a specific transfer could unintentionally disable the feature for other threads as well.

    • Update to 8.5.0-2ubuntu10.7
    Published Updated
  15. CVE-2025-10148

    Medium · CVSS 5.3EPSS 0.52%Fix available

    predictable WebSocket mask

    curl's WebSocket code did not update the 32-bit mask pattern for each new outgoing frame as the specification says. Instead it used a fixed mask that persisted and was used throughout the entire connection. A predictable mask pattern allows for a malicious server to induce traffic between the two communicating parties that could be interpreted by an involved proxy (configured or transparent) as genuine, real, HTTP traffic with content and thereby poison its cache. That cached poisoned content could then be served to all users of that proxy.

    • Update to 8.5.0-2ubuntu10.7
    Published Updated
  16. CVE-2025-0167

    Low · CVSS 3.4EPSS 0.75%Fix available

    netrc and default credential leak

    When asked to use a `.netrc` file for credentials **and** to follow HTTP redirects, curl could leak the password used for the first host to the followed-to host under certain circumstances. This flaw only manifests itself if the netrc file has a `default` entry that omits both login and password. A rare circumstance.

    • Update to 8.5.0-2ubuntu10.8
    Published Updated
  17. CVE-2024-11053

    Low · CVSS 3.4EPSS 1.97%Fix available

    netrc and redirect credential leak

    When asked to both use a `.netrc` file for credentials and to follow HTTP redirects, curl could leak the password used for the first host to the followed-to host under certain circumstances. This flaw only manifests itself if the netrc file has an entry that matches the redirect target hostname but the entry either omits just the password or omits both login and password.

    • Update to 8.5.0-2ubuntu10.6
    Published Updated

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