Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.17.0, turnports_allocate_even() in src/apps/relay/turn_ports.c marks the unused odd sibling port as TPS_TAKEN_ODD for an EVEN-PORT Allocate request with reservation bit R=0 even though no RTCP socket will release it, allowing an authenticated client to permanently exhaust the relay port pool and cause subsequent allocations to fail with STUN error 508. This issue is fixed in version 4.17.0.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-13e2cf6827 advisory.

    # Coturn 4.17.2

    ## What's Changed
      * Fix outgoing UDP TTL pinned to 1 on client-facing sockets

    # Coturn 4.17.1
      * Gate merges on the more tests suites
      * build: Drop ginstall detection in `configure`
      * Flash before socket close

    # Coturn 4.17.0

    ## Upgrade notes     Three defaults changed in this release. Read these before upgrading.

    **DTLS listeners are now opt-in**. The server no longer starts DTLS listeners unless `--dtls` is given. A     deployment that relied on DTLS being up by default will stop serving DTLS clients after the upgrade,     without an error. The deprecated `--no-dtls` / `--no-dtls=false` spellings are still accepted and now     warn.

    **Stateless nonce is on by default**. Challenge nonces are authenticated timestamp cookies rather than a     random value stored per session, so unauthenticated UDP requests are answered from the listener without     allocating a session. Two consequences:

      * The challenge `NONCE` is now 24 characters instead of 16. RFC 8489 requires clients to treat it as an     opaque string of up to 128 characters, so compliant clients are unaffected. `--stateless-nonce=false`     restores the previous behaviour.
      * The signing key is generated per process, so a restart costs each client one `438` re-authentication     round-trip, as does a retry that lands on a different instance behind a load balancer. Set `--stateless-     nonce-secret` to the same value across a fleet to avoid both.

    **The default log line changed**. Timestamps are ISO-8601 with millisecond precision, the thread id is     gone, the field delimiter is a single space instead of `:`, and each record now occupies exactly one line.
    Log shippers and any downstream parsing will need updating; the default line is now:

    ```     2026-08-02T17:32:31.297-0700 INFO Listener address to use: 127.0.0.1     ```

    `--new-log-timestamp=false` restores the legacy seconds-since-start counter.

    ## Security fixes     Three fixes in this release came through the private advisory process. Advisories are still in     preparation; this section will be updated with their identifiers once they are published.

      * **Allocation quotas could be bypassed under `--mobility`**. An authenticated client that repeatedly     created a mobility allocation and disconnected had its quota released while the allocation, its relay     socket and its ticket stayed alive, letting one user hold allocations well past `--user-quota` / `--total-     quota` until the relay port range was exhausted. The charge is now held until final teardown. Regression     coverage: `examples/run_tests_mobility_quota.sh`.
      * **DTLS allocated per-peer state before the cookie was verified**. A ClientHello from an unverified     (and possibly spoofed) source caused a full SSL, socket and session allocation before the source had     proved return routability. The cookie exchange is now performed statelessly via `DTLSv1_listen()`, so an     unanswered ClientHello leaves no state behind. This completes the hardening begun in 4.16.0.
      * **`EVEN-PORT` with the R bit clear leaked relay ports**. The odd sibling port was reserved even when     the client had not asked for it and was never released, so a server would eventually refuse new     allocations that requested `EVEN-PORT`.

    Upgrading is recommended for anyone running `--mobility`, DTLS, or accepting `EVEN-PORT` allocations.

    ## What's Changed
      * Free the secrets list on the `get_user_key` error paths
      * Binding stateless fastpath
      * Worktree stateless nonce mi fastpath
      * Start the DTLS listeners only when `--dtls` is given
      * Do not ask the kernel for an outgoing IP TTL of zero
      * Drop `--simple-log` where it is a no-op alongside `--log-file=stdout`
      * Fix `localtime()` data race in the logger
      * Log format: ISO-8601 timestamp by default, no thread id, space delimiter
      * Keep the legacy random nonce at 16 chars
      * Emit exactly one log line per record
      * Enable stateless nonce by default


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-50c75def83 advisory.

    # Coturn 4.17.2

    ## What's Changed
      * Fix outgoing UDP TTL pinned to 1 on client-facing sockets

    # Coturn 4.17.1
      * Gate merges on the more tests suites
      * build: Drop ginstall detection in `configure`
      * Flash before socket close

    # Coturn 4.17.0

    ## Upgrade notes     Three defaults changed in this release. Read these before upgrading.

    **DTLS listeners are now opt-in**. The server no longer starts DTLS listeners unless `--dtls` is given. A     deployment that relied on DTLS being up by default will stop serving DTLS clients after the upgrade,     without an error. The deprecated `--no-dtls` / `--no-dtls=false` spellings are still accepted and now     warn.

    **Stateless nonce is on by default**. Challenge nonces are authenticated timestamp cookies rather than a     random value stored per session, so unauthenticated UDP requests are answered from the listener without     allocating a session. Two consequences:

      * The challenge `NONCE` is now 24 characters instead of 16. RFC 8489 requires clients to treat it as an     opaque string of up to 128 characters, so compliant clients are unaffected. `--stateless-nonce=false`     restores the previous behaviour.
      * The signing key is generated per process, so a restart costs each client one `438` re-authentication     round-trip, as does a retry that lands on a different instance behind a load balancer. Set `--stateless-     nonce-secret` to the same value across a fleet to avoid both.

    **The default log line changed**. Timestamps are ISO-8601 with millisecond precision, the thread id is     gone, the field delimiter is a single space instead of `:`, and each record now occupies exactly one line.
    Log shippers and any downstream parsing will need updating; the default line is now:

    ```     2026-08-02T17:32:31.297-0700 INFO Listener address to use: 127.0.0.1     ```

    `--new-log-timestamp=false` restores the legacy seconds-since-start counter.

    ## Security fixes     Three fixes in this release came through the private advisory process. Advisories are still in     preparation; this section will be updated with their identifiers once they are published.

      * **Allocation quotas could be bypassed under `--mobility`**. An authenticated client that repeatedly     created a mobility allocation and disconnected had its quota released while the allocation, its relay     socket and its ticket stayed alive, letting one user hold allocations well past `--user-quota` / `--total-     quota` until the relay port range was exhausted. The charge is now held until final teardown. Regression     coverage: `examples/run_tests_mobility_quota.sh`.
      * **DTLS allocated per-peer state before the cookie was verified**. A ClientHello from an unverified     (and possibly spoofed) source caused a full SSL, socket and session allocation before the source had     proved return routability. The cookie exchange is now performed statelessly via `DTLSv1_listen()`, so an     unanswered ClientHello leaves no state behind. This completes the hardening begun in 4.16.0.
      * **`EVEN-PORT` with the R bit clear leaked relay ports**. The odd sibling port was reserved even when     the client had not asked for it and was never released, so a server would eventually refuse new     allocations that requested `EVEN-PORT`.

    Upgrading is recommended for anyone running `--mobility`, DTLS, or accepting `EVEN-PORT` allocations.

    ## What's Changed
      * Free the secrets list on the `get_user_key` error paths
      * Binding stateless fastpath
      * Worktree stateless nonce mi fastpath
      * Start the DTLS listeners only when `--dtls` is given
      * Do not ask the kernel for an outgoing IP TTL of zero
      * Drop `--simple-log` where it is a no-op alongside `--log-file=stdout`
      * Fix `localtime()` data race in the logger
      * Log format: ISO-8601 timestamp by default, no thread id, space delimiter
      * Keep the legacy random nonce at 16 chars
      * Emit exactly one log line per record
      * Enable stateless nonce by default


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.17.0,     turnports_allocate_even() in src/apps/relay/turn_ports.c marks the unused odd sibling port as     TPS_TAKEN_ODD for an EVEN-PORT Allocate request with reservation bit R=0 even though no RTCP socket will     release it, allowing an authenticated client to permanently exhaust the relay port pool and cause     subsequent allocations to fail with STUN error 508. This issue is fixed in version 4.17.0.
    (CVE-2026-73215)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
337078	Fedora 43 : coturn (2026-13e2cf6827)	Nessus	Fedora Local Security Checks	Local	high
337077	Fedora 44 : coturn (2026-50c75def83)	Nessus	Fedora Local Security Checks	Local	high
334664	Linux Distros Unpatched Vulnerability : CVE-2026-73215	Nessus	Misc.	Local	high

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