Classic buffer overflow in the Erlang/OTP megaco flex scanner C driver allows a remote unauthenticated attacker to corrupt the driver's memory (and potentially achieve remote code execution or a denial-of-service crash) by sending a single text-encoded H.248/Megaco message containing an oversized property parm name. When tokenizing a Local/Remote descriptor, mfs_load_property_groups extracts the attacker-controlled property name (bounded only by the message length) and, when no value follows, formats it into a fixed 512-byte error_msg field of the MfsErlDrvData struct using an unchecked sprintf call. Names longer than roughly 452 bytes overflow into the immediately following struct fields (text_buf, text_ptr, term_spec, term_spec_size, term_spec_index), overwriting live pointers and counters with attacker-chosen bytes. Subsequent scanner code writes and frees through the corrupted pointers, producing arbitrary write and arbitrary free primitives inside the BEAM VM process, which can be leveraged for remote code execution. On builds compiled with _FORTIFY_SOURCE the overflow is detected at runtime and terminates the process with SIGABRT, resulting in denial of service. The overflow occurs in the flex scanner before any grammar or Megaco-level authentication processing, so exploitation requires only network reachability to the megaco transport port on a node configured with {scanner, flex}. This vulnerability is associated with program files lib/megaco/src/flex/megaco_flex_scanner_drv.flex.src and program routines mfs_load_property_groups. This issue affects OTP from OTP 17.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to megaco from 3.17.1 before 4.9.1, 4.8.3.1 and 4.7.2.2. Versions prior to OTP 17.0 are also affected but are not listed because the OTP version scheme is only defined from OTP 17.0 onwards.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:3579-1 advisory.

    - CVE-2026-28810: predictable DNS transaction IDs can cause DNS cache poisoning (bsc#1261726).
    - CVE-2026-42789: `public_key` application accepts non-CA certificates as intermediate issuers and this     enables chain       forgery (bsc#1266449).
    - CVE-2026-42790: Name constraints and `Subject CommonName` fallback in TLS hostname verification allows     for certificate       forgery by MITM attacker (bsc#1266466).
    - CVE-2026-42792: permanent `epmd` DoS via connection slot exhaustion due to improper handling of     exceptional       conditions (bsc#1272908).
    - CVE-2026-47078: relative path traversal in `zip:unzip/zip:extract` via `check_dir_level` depth-counter     bypass       (bsc#1272909).
    - CVE-2026-48855: SFTP `READLINK` response leaks absolute backend filesystem path when root is configured     (bsc#1268139).
    - CVE-2026-48856: `httpc` leaks `Authorization` headers to cross-origin redirect targets (bsc#1268141).
    - CVE-2026-48858: server-side request forgery allows FTP bounce attacks and SSRF via an unvalidated `PASV`     response IP       address (bsc#1268142).
    - CVE-2026-48860: `ssl` (`inet_tls_dist` module) allows unauthenticated bypass of the distribution-over-     TLS LAN       allowlist (bsc#1268146).
    - CVE-2026-49759: unbounded stack buffer overflow in SCTP error cause parsing in `inet_drv` (bsc#1268163).
    - CVE-2026-49760: stack buffer overflow in `ei_s_print_term` at very large integer (bsc#1268164).
    - CVE-2026-53422: SFTP `REALPATH` path-existence oracle allows filesystem enumeration outside configured     root       (bsc#1270245).
    - CVE-2026-54886: SSH SFTP server denial of service via extended channel data infinite loop (bsc#1270246).
    - CVE-2026-54887: use of default cryptographic key allows predictable DTLS cookie computation during the     startup window       (bsc#1270247).
    - CVE-2026-54891: plaintext injection towards (D)TLS client during handshake (bsc#1270250).
    - CVE-2026-55737: heap pointer corruption via signed/unsigned mismatch in `LARGE_TUPLE_EXTP` decoding in     `erts`       external term format decoder (bsc#1272910).
    - CVE-2026-55950: time-of-check time-of-use race condition allows an unauthenticated remote attacker to     crash all active       DTLS sessions on a listener (bsc#1270253).
    - CVE-2026-55952: missing validation allows for DoS of the TLS-1.3 server when clients send a malformed     `ClientHello`       with mismatched PSK identity and binder list lengths (bsc#1270258).
    - CVE-2026-55953: TLS 1.2 and DTLS clients accept unoffered anonymous cipher suites and allow for server     authentication       bypass (bsc#1272911).
    - CVE-2026-58227: TLS/DTLS denial of service via unbounded recursion on cross-signed peer certificate     chain       (bsc#1272913).
    - CVE-2026-59250: `megaco` flex scanner buffer overflow via oversized property parm name (bsc#1272914).
    - CVE-2026-59251: denial of service via exponential certificate policy tree growth in path validation     (bsc#1272915).

Tenable has extracted the preceding description block directly from the SUSE 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 version of Erlang/OTP installed on the remote host is 17.0 prior to 27.3.4.15, 28.0 prior to 28.5.0.4, or 29.0 prior to 29.0.4. It is, therefore, affected by multiple vulnerabilities:

  - The Erlang/OTP ssl TLS 1.2 (and earlier) and DTLS client does not verify that the cipher suite     selected by the server in ServerHello was among the suites offered by the client in ClientHello.
    An on-path attacker can respond with a ServerHello selecting an anonymous key exchange suite,     bypassing certificate validation and allowing interception of traffic. (CVE-2026-55953)

  - Classic buffer overflow in the Erlang/OTP megaco flex scanner C driver allows a remote     unauthenticated attacker to corrupt the driver's memory by sending a single text-encoded     H.248/Megaco message containing an oversized property parm name. (CVE-2026-59250)

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.

  - Classic buffer overflow in the Erlang/OTP megaco flex scanner C driver allows a remote unauthenticated     attacker to corrupt the driver's memory (and potentially achieve remote code execution or a denial-of-     service crash) by sending a single text-encoded H.248/Megaco message containing an oversized property parm     name. When tokenizing a Local/Remote descriptor, mfs_load_property_groups extracts the attacker-controlled     property name (bounded only by the message length) and, when no value follows, formats it into a fixed     512-byte error_msg field of the MfsErlDrvData struct using an unchecked sprintf call. Names longer than     roughly 452 bytes overflow into the immediately following struct fields (text_buf, text_ptr, term_spec,     term_spec_size, term_spec_index), overwriting live pointers and counters with attacker-chosen bytes.
    Subsequent scanner code writes and frees through the corrupted pointers, producing arbitrary write and     arbitrary free primitives inside the BEAM VM process, which can be leveraged for remote code execution. On     builds compiled with _FORTIFY_SOURCE the overflow is detected at runtime and terminates the process with     SIGABRT, resulting in denial of service. The overflow occurs in the flex scanner before any grammar or     Megaco-level authentication processing, so exploitation requires only network reachability to the megaco     transport port on a node configured with {scanner, flex}. This vulnerability is associated with program     files lib/megaco/src/flex/megaco_flex_scanner_drv.flex.src and program routines mfs_load_property_groups.
    This issue affects OTP from OTP 17.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to     megaco from 3.17.1 before 4.9.1, 4.8.3.1 and 4.7.2.2. Versions prior to OTP 17.0 are also affected but are     not listed because the OTP version scheme is only defined from OTP 17.0 onwards. (CVE-2026-59250)

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

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 445da2cc-89e1-11f1-b35c-4c526214c986 advisory.

    https://github.com/erlang/otp/security/advisories/GHSA-7xgh-gmgf-q2g7 reports:
    A remote unauthenticated attacker can crash Erlang nodes               running the megaco text codec with the flex scanner option by               sending an H.248/Megaco message with a property parm name               exceeding 452 bytes. The overflow occurs in a C linked-in               driver, causing the entire BEAM VM process to terminate. It is               reachable pre-authentication, as the flex scanner processes               raw TCP payloads before protocol validation.

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

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

ID	Name	Product	Family	Type	Severity
335097	SUSE SLES15 Security Update : erlang26 (SUSE-SU-2026:3579-1)	Nessus	SuSE Local Security Checks	Local	critical
331349	Erlang/OTP 17.0 < 27.3.4.15 / 28.0 < 28.5.0.4 / 29.0 < 29.0.4 Multiple Vulnerabilities	Nessus	Misc.	Local	critical
330404	Linux Distros Unpatched Vulnerability : CVE-2026-59250	Nessus	Misc.	Local	high
330269	FreeBSD : Erlang/OTP -- megaco flex scanner buffer overflow (445da2cc-89e1-11f1-b35c-4c526214c986)	Nessus	FreeBSD Local Security Checks	Local	high

Detections

Analytics

CVE-2026-59250

high

Tenable Plugins

critical

critical

high

high