Patch Package OTP 27.3.4.17 Released
Erlang/OTP
otp@REDACTED
Tue Sep 1 15:31:32 CEST 2026
Patch Package: OTP 27.3.4.17
Git Tag: OTP-27.3.4.17
Date: 2026-09-01
Trouble Report Id: OTP-20135, OTP-20234, OTP-20264, OTP-20265,
OTP-20268, OTP-20269, OTP-20270, OTP-20271,
OTP-20273, OTP-20278, OTP-20279, OTP-20281,
OTP-20282, OTP-20284, OTP-20289, OTP-20296,
OTP-20302, OTP-20306, OTP-20307, OTP-20308,
OTP-20312, OTP-20319, OTP-20320, OTP-20324,
OTP-20330, OTP-20333, OTP-20334, OTP-20342,
OTP-20343, OTP-20344, OTP-20345, OTP-20346,
OTP-20347, OTP-20349, OTP-20351
Seq num: CVE-2026-75538, ERIERL-1352, GH-11052,
GH-11278, GH-11308, GH-11380, GH-11404,
GH-11419, GH-11423, GH-11494, GH-11511,
OTP-20037, OTP-20199, PR-11247, PR-11285,
PR-11325, PR-11388, PR-11425, PR-11428,
PR-11429, PR-11437, PR-11463, PR-11464,
PR-11478, PR-11481, PR-11492, PR-11503,
PR-11505, PR-11509, PR-11513, PR-11517,
PR-11521, PR-11533, PR-11538, PR-11539,
PR-11540, PR-11541, PR-11542, PR-11543,
PR-11544, PR-11545, PR-11546, PR-11547,
PR-11548, PR-11554
System: OTP
Release: 27
Application: compiler-8.6.1.6, crypto-5.5.3.5,
eldap-1.2.14.2, erl_interface-5.5.2.2,
erts-15.2.7.13, inets-9.3.2.7,
kernel-10.2.7.5, megaco-4.7.2.3,
mnesia-4.23.5.4, snmp-5.18.2.1,
ssh-5.2.11.12, ssl-11.2.12.12,
stdlib-6.2.2.5, tools-4.1.1.1
Predecessor: OTP 27.3.4.16
Check out the git tag OTP-27.3.4.17, 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.
# compiler-8.6.1.6
The compiler-8.6.1.6 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- compiler: Fix bug in beam_types:subtract/2 for bitstrings
Own Id: OTP-20312
Related Id(s): GH-11494, PR-11503
> #### Full runtime dependencies of compiler-8.6.1.6
>
> crypto-5.1, erts-13.0, kernel-8.4, stdlib-6.0
# crypto-5.5.3.5
The crypto-5.5.3.5 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- Fixed type mismatch between `ErlNifUInt64` and `uint64_t` in crypto NIF that
caused incompatible-pointer warnings on macOS arm64 when passing DH parameters
to OpenSSL.
Own Id: OTP-20333
Related Id(s): GH-11511, PR-11513
> #### Full runtime dependencies of crypto-5.5.3.5
>
> erts-9.0, kernel-5.3, stdlib-3.9
# eldap-1.2.14.2
The eldap-1.2.14.2 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- eldap referral URL parsing now rejects a port component longer than 5 digits
instead of attempting to convert an arbitrarily large digit string to an
integer.
Own Id: OTP-20345
Related Id(s): PR-11538
> #### Full runtime dependencies of eldap-1.2.14.2
>
> asn1-3.0, erts-6.0, kernel-3.0, ssl-5.3.4, stdlib-3.4
# erl_interface-5.5.2.2
The erl_interface-5.5.2.2 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- erl_interface: Fix buffer leak and state corruption on `ei_x_buff` realloc
failure
Own Id: OTP-20324
Related Id(s): PR-11492
# erts-15.2.7.13
The erts-15.2.7.13 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- No-suspend port command signals (i.e. port command signals sent using the
erlang:port_command/3 BIF or the erlang:send/3 BIF with the `nosuspend`
option) were not aborted properly in all scenarios which could leave the port
queue in a busy state indefinitely. Also asynchronously sent no-suspend
command signals (i.e, port command signals sent using the erlang:send/3 BIF
with the `nosuspend` option) could sometimes be delivered even though the port
was busy.
Own Id: OTP-20135
Related Id(s): GH-11052, PR-11463
- erts: Fix missing exit_status caused by SIGCHLD race
Own Id: OTP-20273
Related Id(s): GH-11278, PR-11285
- erts: Fix bug in `is_in_range` instruction for x86 JIT
Own Id: OTP-20278
Related Id(s): GH-11419, PR-11429
- Fixed bug in `binary_to_term` that could cause emulator crash for specific
terms in specific process states (reductions left).
Own Id: OTP-20281
Related Id(s): GH-11404, PR-11425
- erts: Fix crash with `term_to_iovec/2` for large binary
Own Id: OTP-20282
Related Id(s): PR-11428
- A monitor of `time_offset` co-created with a process alias
(`monitor(time_offset, clock_service, {alias, UnaliasOpt})`) either crashed
the runtime system or did not work. This bug was introduced in OTP 25.0.
Own Id: OTP-20319
Related Id(s): PR-11509
- A process alias was erroneously created when a remote `spawn_request()`
operation with a `{monitor, {alias, explicit_unalias}}` option failed with
`noconnection` reason.
Own Id: OTP-20330
Related Id(s): PR-11521
- A `gen_tcp` socket using the inet driver and `{packet,4}` had a bug if
receiving a packet with size just below INT_MAX.
That packet size wrapped in size calculations and made the received data
overwrite its allocation and trash allocator metadata and subsequent block(s),
causing the VM to crash.
This made it possible for anyone to remotely crash an Erlang node that used
`{packet,4}` on a reachable socket.
This bug has been corrected.
Own Id: OTP-20334
Related Id(s): PR-11533, CVE-2026-75538
> #### Full runtime dependencies of erts-15.2.7.13
>
> kernel-9.0, sasl-3.3, stdlib-4.1
# inets-9.3.2.7
The inets-9.3.2.7 application can be applied independently of other applications
on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- The `dets` and `mnesia` `mod_auth` backends used a key that did not include
the directory path, so all `require_user`/`require_group` records collapsed
into one per-listener namespace. A user authorized for one protected directory
could authenticate against any other protected directory served by the same
listener. `{path, Directory}` is now included in the auth backend key, scoping
records per directory as documented.
Own Id: OTP-20264
Related Id(s): PR-11546
- Requests specifying both `Transfer-Encoding` and `Content-Length` headers are
now rejected with `400 Bad Request`, per RFC 9112 Section 6.3. Previously such
requests could be used for CL.TE request-smuggling/desync attacks against
reverse proxies in front of `httpd`.
Own Id: OTP-20268
Related Id(s): PR-11547
- `httpd` accepted the obsolete header line-folding syntax (RFC 9112 Section
5.2, a continuation line beginning with space/tab), silently treating the
folded continuation as a separate header. This allowed CL.TE-style request
smuggling when `httpd` was placed behind a folding-aware proxy. Such requests
are now rejected with `400 Bad Request`.
Own Id: OTP-20269
Related Id(s): PR-11544
- A header such as `Content-Length : 6` (whitespace before the colon) was
previously silently dropped, causing the content length to default to 0 and
the body bytes to be misinterpreted as a pipelined request (CL.0 smuggling).
Per RFC 7230 Section 3.2.4, such headers are now rejected with
`400 Bad Request`.
Own Id: OTP-20270
Related Id(s): PR-11545
- A new httpd option `request_timeout` (default 60 seconds, renamed from the
interim `max_body_read_timeout`) bounds the idle time between reads of a
request body/message. The server now also sends `408 Request Timeout` when the
`min_bytes_per_second` floor is hit, and `keep_alive_timeout` measurement was
corrected so the timer is cancelled as soon as new data arrives rather than
only after full header parsing; `keep_alive_timeout` and `request_timeout` now
also accept `infinity` to disable the timeout.
Own Id: OTP-20271
Related Id(s): PR-11543
- `mod_auth`, `mod_security`, and `mod_get` compared resolved filesystem paths
against configured protected-directory patterns without normalizing repeated
slashes or filesystem case. On case-insensitive filesystems (macOS, Windows)
or with repeated slashes, a request could resolve to a protected resource
while evading the directory match. Paths are now canonicalized
(slash-collapsed, and case-normalized when the filesystem is case-insensitive)
before the authorization decision.
Own Id: OTP-20279
Related Id(s): PR-11542
- A request with an invalid chunked transfer-encoding chunk size previously
caused the httpd connection handler to hang indefinitely without requiring
further input from the client. This leaked a process per request and could be
used to exhaust server resources (denial of service). Invalid chunk sizes are
now rejected immediately with an error response, and the connection is closed.
Own Id: OTP-20306
Related Id(s): PR-11539
- `max_body_size` was previously enforced only after a complete chunk had been
received, allowing a single oversized chunk to be buffered in full before the
limit was checked — undermining the memory-exhaustion protection the option is
meant to provide. The limit is now enforced incrementally as chunk data
arrives, rejecting the request as soon as the configured size is exceeded.
Own Id: OTP-20307
Related Id(s): PR-11540
- The documented default of 150 for the `max_clients` option was not applied by
the implementation, allowing an unbounded number of concurrent clients to
connect regardless of configuration. The default is now correctly enforced.
Own Id: OTP-20308
Related Id(s): PR-11541
- Fixed a bug where httpd failed to start when configured with {socket_type,
{ip_comm, SockOpts}} and a fixed (non-zero) port.
Own Id: OTP-20342
Related Id(s): PR-11548
- `httpc` now enforces a limit on the total size of response headers and
response body, preventing unbounded memory allocation when connecting to a
malicious or malfunctioning server. The new max_header_size and max_body_size
request options can be used to override the default limit (10240 bytes for
headers). Additionally, httpc now validates that the Content-Length header
contains only digits before use, avoiding a crash on malformed responses.
Own Id: OTP-20343
Related Id(s): PR-11538
> #### Full runtime dependencies of inets-9.3.2.7
>
> 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
# kernel-10.2.7.5
Note! The kernel-10.2.7.5 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:
-- erts-15.2.5 (first satisfied in OTP 27.3.2)
## Fixed Bugs and Malfunctions
- A field in `net_kernel`'s internal state was not cleaned up in some cases for
failed connections could cause the state to grow indefinitely over time. This
has now been fixed.
Own Id: OTP-20265
Related Id(s): GH-11308, PR-11388
- Handling of the truncation bit in `inet_res` has been fixed so it properly
falls back to querying over TCP after a truncated UDP reply.
This fixes a bug introduced in OTP-27.3.4.10, kernel-10.2.7.4 making a
truncated UDP answer fail to parse and never execute the fallback, instead the
name resolve operation fails.
Own Id: OTP-20349
Related Id(s): ERIERL-1352, PR-11247, OTP-20037, OTP-20199
> #### Full runtime dependencies of kernel-10.2.7.5
>
> crypto-5.0, erts-15.2.5, sasl-3.0, stdlib-6.0
# megaco-4.7.2.3
The megaco-4.7.2.3 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- Numeric fields in megaco text-encoded messages are now validated for
digit-string length before integer conversion, improving robustness of the
text decoder. Per-field digit limits based on the H.248.1 ASN.1 type
constraints are enforced (e.g., 10 digits for UINT32, 2 digits for timer
values), along with a 100 KB overall message size cap at the scanner entry
point. The binary (BER/PER) codec is not affected.
Own Id: OTP-20234
Related Id(s): PR-11325
> #### Full runtime dependencies of megaco-4.7.2.3
>
> asn1-3.0, debugger-4.0, erts-12.0, et-1.5, kernel-8.0, runtime_tools-1.8.14,
> stdlib-2.5
# mnesia-4.23.5.4
The mnesia-4.23.5.4 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- A transaction iterating a table (first/1, last/1, next/2, prev/2, select,
select_reverse on non-ordered_set) leaked a safe_fixtable hold when the
coordinator was killed by an external signal. The table remained fixed for the
lifetime of the node, preventing space reclamation of deleted objects.
Own Id: OTP-20347
Related Id(s): PR-11517
- Fixed a race condition where mnesia_controller could crash if a table was
deleted while mnesia:set_master_nodes/2 was being processed.
Own Id: OTP-20351
Related Id(s): PR-11554
> #### Full runtime dependencies of mnesia-4.23.5.4
>
> erts-9.0, kernel-5.3, stdlib-5.0
# snmp-5.18.2.1
The snmp-5.18.2.1 application can be applied independently of other applications
on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- The SNMP PDU decoder now bounds the byte length accepted for INTEGER,
Counter32, Gauge32/Unsigned32, TimeTicks, and Counter64 values during decoding
(4, 5, 5, 5, and 9 bytes respectively, matching the SMIv2 value ranges),
instead of accepting an arbitrarily large byte string and converting it to an
integer.
Own Id: OTP-20346
Related Id(s): PR-11538
> #### Full runtime dependencies of snmp-5.18.2.1
>
> crypto-4.6, erts-12.0, kernel-8.0, mnesia-4.12, runtime_tools-1.8.14,
> stdlib-5.0
# ssh-5.2.11.12
The ssh-5.2.11.12 application can be applied independently of other applications
on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- Fixed a bug where multiple subsystem requests could succeed on same ssh
channel which is forbidden by RFC 4254 §6.5
Own Id: OTP-20284
Related Id(s): PR-11437
> #### Full runtime dependencies of ssh-5.2.11.12
>
> 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-11.2.12.12
Note! The ssl-11.2.12.12 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)
## Improvements and New Features
- Hardening improvements of the ssl application.
TLS distribution now defaults to TLS-1.3 instead of TLS-1.2 (TLS-1.2 is kept
as fallback for rolling upgrades).
TLS-1.2 server with {verify, verify_peer} now defaults reuse_sessions to false
to mitigate the Triple Handshake attack (RFC 7627). Set {reuse_sessions, true}
explicitly to restore previous behavior.
Various missing or faulty sanity checks added and TLS alerts adjusted to
comply with RFC MUST requirements, including: signature algorithm validation
for intermediate certificates, TLS-1.3 session_id echo, pre_shared_key
extension ordering, and renegotiation_info enforcement.
Hardened and improved CRL support. Introduces new option allowed_hosts for the
optional CRL HTTP fetching feature to restrict which hosts may be contacted.
Internal/loopback IPs are now blocked by default (SSRF protection).
TLS-1.3 client ticket handling is more robust (locked tickets are released on
client crash). Server TLS-1.3 ticket handling and anti-replay Bloom filter
performance are optimized.
DTLS duplicate ChangeCipherSpec handling simplified, fixing potential state
machine confusion (GH-11075).
Process state formatting no longer leaks secrets in crash logs.
Own Id: OTP-20289
Related Id(s): PR-11478
> #### Full runtime dependencies of ssl-11.2.12.12
>
> 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
# stdlib-6.2.2.5
The stdlib-6.2.2.5 application can be applied independently of other
applications on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- Fixed a bug in unicode_util:gc/1 where the grapheme cluster segmentation of
`$\r` (not followed by `$\n`) would decompose binary continuations into mixed
chardata. This caused string:trim/3 (and string:chomp/1) to return
incorrect results or crash when trimming strings containing binaries followed
by another list element.
Own Id: OTP-20296
Related Id(s): GH-11380, PR-11464
- When compiling a module with a triple-quoted string with escape sequences and
a chunk boundary happened to fall just after an escape character, that
character was not passed to the reentrancy continuation, so the scanner
interpreted the following characters as not an escape sequence.
This bug has now been fixed.
Own Id: OTP-20320
Related Id(s): GH-11423, PR-11505
- uri_string:parse/1 now rejects URIs with an unreasonably long port component
(more than 5 digits) instead of attempting to convert an arbitrarily large
digit string to an integer.
Own Id: OTP-20344
Related Id(s): PR-11538
> #### Full runtime dependencies of stdlib-6.2.2.5
>
> compiler-5.0, crypto-4.5, erts-15.0, kernel-10.0, sasl-3.0
# tools-4.1.1.1
The tools-4.1.1.1 application can be applied independently of other applications
on a full OTP 27 installation.
## Fixed Bugs and Malfunctions
- tools: fixes tprof not stopping tracing
A call to `tprof:enable_trace(new|existing)` starts tracing processes. To stop
it, one calls `tprof:disable_trace(new|existing)`. However, the guard to stop
tracing was matching on `new_processes | existing_processes`. The return
happens to say `0` processes are traced now, but the tracing did not stop.
This issue has been fixed.
Own Id: OTP-20302
Related Id(s): PR-11481
> #### Full runtime dependencies of tools-4.1.1.1
>
> compiler-8.5, erts-15.0, erts-15.0, kernel-10.0, runtime_tools-2.1, stdlib-6.0
# Thanks to
Laurynas ÄŒetyrkinas, ruslandoga, Thomas Cioppettini
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