Patch Package OTP 27.3.4.19 Released

Erlang News & Announcements Erlang News
1 
Patch Package:           OTP 27.3.4.19
Git Tag:                 OTP-27.3.4.19
Date:                    2026-10-14
Trouble Report Id:       OTP-20360, OTP-20385, OTP-20392, OTP-20394,
                         OTP-20408, OTP-20418, OTP-20420, OTP-20423,
                         OTP-20426, OTP-20427, OTP-20428, OTP-20430,
                         OTP-20437, OTP-20438, OTP-20439, OTP-20442,
                         OTP-20445, OTP-20456
Seq num:                 CVE-2026-105236, CVE-2026-42789,
                         CVE-2026-48856, CVE-2026-94200, ERIERL-1362,
                         ERIERL-1367, GH-11620, GH-11702, GH-11709,
                         GH-11735, GH-11748, GH-SA-m75x-4vwg-ggjh,
                         GH-SA-q7cq-pfgf-5hr7, OTP-20155, OTP-20346,
                         PR-11561, PR-11623, PR-11662, PR-11692,
                         PR-11707, PR-11708, PR-11720, PR-11727,
                         PR-11751, PR-11753, PR-11755, PR-11767,
                         PR-11773, PR-11808, PR-11823, PR-11824,
                         PR-11825
System:                  OTP
Release:                 27
Application:             compiler-8.6.1.8, erts-15.2.7.14,
                         inets-9.3.2.8, mnesia-4.23.5.6,
                         odbc-2.15.0.1, public_key-1.17.1.7,
                         snmp-5.18.2.2, ssh-5.2.11.14, ssl-11.2.12.14
Predecessor:             OTP 27.3.4.18

Check out the git tag OTP-27.3.4.19, and build a full OTP system including
documentation. Apply one or more applications from this build as patches to your
installation using the ‘otp_patch_apply’ tool. For information on install
requirements, see descriptions for each application version below.

POTENTIAL INCOMPATIBILITIES

  • When the max_channels limit is reached for a port-forwarding channel
    (direct-tcpip or forwarded-tcpip), the SSH daemon now refuses the individual
    channel with SSH_MSG_CHANNEL_OPEN_FAILURE and keeps the connection alive,
    instead of terminating the whole SSH connection. Port-forwarding channels now
    behave like session channels, which already survived the limit, and this
    matches OpenSSH. Applications that relied on the connection being closed when
    the channel limit was reached must instead handle the channel-open failure.

    Own Id: OTP-20420
    Application(s): ssh
    Related Id(s): PR-11708

compiler-8.6.1.8

The compiler-8.6.1.8 application can be applied independently of other
applications on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Compilation of a function with thousands of clauses would be very slow.

    Own Id: OTP-20437
    Related Id(s): GH-11735, PR-11767

  • Sometimes compiling with deterministic would not guarantee generation of
    identical BEAM files for every build.

    Own Id: OTP-20438
    Related Id(s): GH-11748, PR-11753

Full runtime dependencies of compiler-8.6.1.8

crypto-5.1, erts-13.0, kernel-8.4, stdlib-6.0

erts-15.2.7.14

The erts-15.2.7.14 application can be applied independently of other
applications on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Two trace sessions that trace garbage_collection on the same process crash
    the emulator on the first collection.

    trace_gc() in erl_trace.c builds the GC info list on a temporary heap for
    the first session and frees it inside the session loop. The next session
    reuses msg, which now points into freed memory.

    The memory is now freed after the session loop, which removes the
    use-after-free.

    Own Id: OTP-20385
    Related Id(s): PR-11623

Full runtime dependencies of erts-15.2.7.14

kernel-9.0, sasl-3.3, stdlib-4.1

inets-9.3.2.8

The inets-9.3.2.8 application can be applied independently of other applications
on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Credentials supplied in the userinfo component of a request URI
    (http://user``:password@host/path) were still sent to the redirect target when
    httpc followed a cross-origin redirect. The userinfo component is now
    cleared together with the sensitive headers whenever the redirect target
    differs in host or port from the original request. Redirects that stay within
    the same origin are unaffected and still carry the credentials.

    Own Id: OTP-20456
    Related Id(s): GH-SA-m75x-4vwg-ggjh, PR-11825, CVE-2026-48856, OTP-20155

Full runtime dependencies of inets-9.3.2.8

erts-14.0, kernel-9.0, mnesia-4.12, public_key-1.13, runtime_tools-1.8.14,
ssl-9.0, stdlib-5.0, stdlib-6.0

mnesia-4.23.5.6

The mnesia-4.23.5.6 application can be applied independently of other
applications on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Fixed the type specification for mnesia:restore/2, which incorrectly listed
    the operation restore_tables instead of recreate_tables, causing Dialyzer
    to reject valid calls and accept invalid ones.

    Own Id: OTP-20442
    Related Id(s): PR-11755

Full runtime dependencies of mnesia-4.23.5.6

erts-9.0, kernel-5.3, stdlib-5.0

odbc-2.15.0.1

The odbc-2.15.0.1 application can be applied independently of other applications
on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Fix error handling to avoid possible memory issues that could cause odbc port
    program to fail.

    Own Id: OTP-20439
    Related Id(s): PR-11808

Full runtime dependencies of odbc-2.15.0.1

erts-6.0, kernel-3.0, stdlib-2.0

public_key-1.17.1.7

The public_key-1.17.1.7 application can be applied independently of other
applications on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Enforce the RFC 5280 basic-constraints CA checks for X.509 version 1 and
    version 2 certificates during certificate path validation. A v1/v2 certificate
    carries no extensions and therefore no basicConstraints, so it must never be
    accepted as a CA; such a certificate is now rejected in issuer position with
    {bad_cert, missing_basic_constraint} while remaining valid as a leaf. This
    closes the version-1 path left uncovered by the earlier CVE-2026-42789 fix.

    Own Id: OTP-20423
    Related Id(s): PR-11727, CVE-2026-42789

Full runtime dependencies of public_key-1.17.1.7

asn1-5.0, crypto-5.0, erts-13.0, kernel-8.0, stdlib-4.0

snmp-5.18.2.2

The snmp-5.18.2.2 application can be applied independently of other applications
on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • The SNMP agent no longer fails to answer an SNMPv3 message whose msgUserName
    matches the configured terminating-discovery trigger_username (by default the
    empty string) and whose msgAuthoritativeEngineID is the agent’s own engine ID.
    Such a message is not a stage-1 discovery request, but the agent treated it as
    one and then failed while generating the report, logging a configuration error
    and discarding the request without responding. The agent now answers it with a
    usmStatsUnknownUserNames report, as prescribed by RFC 3414, section 3.2. As a
    consequence of the same change, a message carrying the trigger user name
    together with an unknown, non-empty engine ID is now answered with a
    usmStatsUnknownEngineIDs report instead of being silently discarded.

    Own Id: OTP-20427
    Related Id(s): ERIERL-1362, PR-11823

  • The byte-length bounds added in OTP-20346 for varbind values now apply to
    every integer field decoded by snmp_pdus: the v3 header fields msgID,
    msgMaxSize and msgSecurityModel, the USM security parameters
    msgAuthoritativeEngineBoots and msgAuthoritativeEngineTime, and the PDU fields
    request-id, error-status, error-index, non-repeaters, max-repetitions,
    generic-trap and specific-trap. Each field accepts at most the number of BER
    content octets that its type requires, instead of an arbitrary number of
    octets that were converted into a large integer. An over-long integer is now
    signalled with an exit rather than a throw. Code that calls the exported
    snmp_pdus decode functions inside a catch will receive {‘EXIT’, Reason} where
    it previously received the thrown term directly. Inside the agent and manager,
    such a message is now discarded and counted in snmpInASNParseErrs; previously
    it caused a case_clause failure during message processing.

    Own Id: OTP-20428
    Related Id(s): GH-SA-q7cq-pfgf-5hr7, PR-11824, OTP-20346

Full runtime dependencies of snmp-5.18.2.2

crypto-4.6, erts-12.0, kernel-8.0, mnesia-4.12, runtime_tools-1.8.14,
stdlib-5.0

ssh-5.2.11.14

The ssh-5.2.11.14 application can be applied independently of other applications
on a full OTP 27 installation.

Fixed Bugs and Malfunctions

  • Fixed the following bugs in the SSH application:

    • The SFTP client (ssh_sftp) checked the channel state record against 0
      instead of the exit status integer when handling an exit_status message. The
      success branch was therefore dead code, and every SFTP subsystem exit —
      including a clean exit with status 0 — was reported to callers as an error.
      A clean exit is now reported as a normal stop.
    • The SSH_FXP_EXTENDED_REPLY decoder in ssh_xfer bound only a single byte of
      the reply payload instead of the full binary (the pattern was missing a
      /binary specifier). This made SFTP extension operations such as
      statvfs@openssh.com fail with a function_clause crash whenever the payload
      was not exactly one byte.
    • The TCP forwarding acceptor supervisor used the default permanent restart
      strategy, causing the acceptor to be restarted unnecessarily when a
      forwarded socket closed normally. The child now uses a transient restart
      strategy.
    • The keyboard_interact_fun handling returned the atom nok instead of not_ok
      on an invalid response, causing a crash during SSH message encoding instead
      of a clean authentication rejection.
    • The ssh*client_channel catch pattern error:{undef, *} never matched Erlang’s
      actual error:undef exception, so a missing optional handle_call/3 or
      handle_cast/2 callback crashed the channel process instead of being ignored.
      The catch now matches error:undef and uses erlang:function_exported/3 to
      tell a genuinely missing optional callback (ignored, as before) from an
      undef raised deeper inside an implemented callback (now re-raised instead of
      being silently swallowed).
    • Both ssh_tcpip_forward_client and ssh_tcpip_forward_srv called
      gen_tcp:close(undefined) in terminate/2 when the forwarding socket was never
      established (or already closed), producing noisy crash reports on normal
      forward teardown. terminate/2 now handles the undefined socket.

    Own Id: OTP-20360
    Related Id(s): PR-11561

  • Fixed an SSH port-forwarding acceptor crash triggered by a peer that connects
    and immediately resets the connection. Transient TCP errors from accept and
    peername are now handled gracefully instead of terminating the acceptor.

    Own Id: OTP-20392
    Related Id(s): PR-11720

  • When the max_channels limit is reached for a port-forwarding channel
    (direct-tcpip or forwarded-tcpip), the SSH daemon now refuses the individual
    channel with SSH_MSG_CHANNEL_OPEN_FAILURE and keeps the connection alive,
    instead of terminating the whole SSH connection. Port-forwarding channels now
    behave like session channels, which already survived the limit, and this
    matches OpenSSH. Applications that relied on the connection being closed when
    the channel limit was reached must instead handle the channel-open failure.

    Own Id: OTP-20420
    Related Id(s): PR-11708

    *** POTENTIAL INCOMPATIBILITY ***

Full runtime dependencies of ssh-5.2.11.14

crypto-5.0, erts-14.0, kernel-9.0, public_key-1.6.1, runtime_tools-1.15.1,
stdlib-5.0, stdlib-6.0

ssl-11.2.12.14

Note! The ssl-11.2.12.14 application cannot be applied independently of other
applications on an arbitrary OTP 27 installation.

   On a full OTP 27 installation, also the following runtime
   dependency has to be satisfied:
   -- public_key-1.17.1.3 (first satisfied in OTP 27.3.4.12)

Fixed Bugs and Malfunctions

  • DoS attack prevention missed corner case, now fall back to the incomplete
    peer-only chain handling when paths/2 yields no path, restoring the OTP 28
    behavior and matching OpenSSL, curl and browsers. The digraph and its
    chain-length limit from PR #11343 are unchanged, so the DoS protection is
    preserved; the extra cost is one trust-store lookup, as for a leaf-only chain.

    Own Id: OTP-20394
    Related Id(s): GH-11620, PR-11662

  • The equivalent options dh and dhfile where unintentionally ignored and the
    default value was used instead.

    Own Id: OTP-20408
    Related Id(s): ERIERL-1367, PR-11692

  • Redesign TLS-1.3 auto client ticket handling to adhere to RFC single-use by
    consuming a ticket when offered removing it from the client ticket store. This
    resolves unnecessary connections errors for concurrent client connections that
    previously could end up trying to use the same ticket, or tickets being
    evicted form the client store when a client still needed to look it up.

    Own Id: OTP-20418
    Related Id(s): GH-11702, GH-11709, PR-11707

  • Validate the handshake message type when decoding TLS-1.3 hello extensions
    (RFC 8446 / RFC 9846). A malicious or man-in-the-middle TLS-1.3 server could
    send a NewSessionTicket carrying a zero-length early_data extension, which a
    client with automatic session-ticket management (session_tickets => auto)
    stored and then crashed on during a later resumption, taking down the
    node-global client ticket store and disrupting TLS-1.3 resumption for the
    whole node. Extensions are now decoded only in the handshake messages in which
    they are permitted, so such a ticket is ignored instead of poisoning the
    store. This avoids a denial-of-service possibility.

    Own Id: OTP-20426
    Related Id(s): PR-11773, CVE-2026-94200

  • Fix a tls_sender crash during Erlang distribution over TLS (-proto_dist
    inet_tls). When a distribution peer disappeared while data was still being
    sent to it, the sender process crashed with a function_clause in gen:reply/2
    instead of tearing the connection down cleanly. As a side effect the surviving
    node reported a nodedown_reason of {function_clause, …} rather than a normal
    teardown reason, which could confuse code that distinguishes a planned
    shutdown from a genuine failure.

    Own Id: OTP-20430
    Related Id(s): PR-11751

  • Fixed a TLS/DTLS session resumption flaw ((D)TLS-1.2 abbreviated handshake)
    where an SNI-aware server could resume a cached session even when the
    resumption request’s server_name differed from the one that established the
    session, violating RFC 6066 §3. In virtual-hosting deployments where several
    SNI names share one server certificate but apply different
    client-authentication trust, a client could resume a session established under
    one SNI name while connecting under another — bypassing the second virtual
    service’s client-authentication boundary and skipping the certificate
    exchange.

    The server now binds the establishing SNI hostname to the session and refuses
    resumption (falling back to a full handshake) when the requested SNI differs.
    A request without SNI only matches a session established without SNI, so
    ordinary non-SNI resumption is unaffected.

    As a related correction, a listener’s derived reuse_sessions default (enabled
    under verify_none) is no longer carried into an SNI virtual service that
    switches to verify_peer; such a service must enable reuse_sessions explicitly.

    Own Id: OTP-20445
    Related Id(s): PR-11773, CVE-2026-105236

Full runtime dependencies of ssl-11.2.12.14

crypto-5.1, erts-15.0, inets-5.10.7, kernel-9.0, public_key-1.17.1.3,
runtime_tools-1.15.1, stdlib-6.0

Thanks to

Alexey Aristov, Daniel Gorin, Marko Mindek

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