Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to enumerate the existence of files and directories outside the configured root directory. The SSH_FXP_REALPATH handler in ssh_sftpd calls relate_file_name/3 with Canonicalize=false, unlike every other SFTP operation handler. This allows .. components in the requested path to bypass the is_within_root/2 check without being resolved. The un-canonicalized path then enters resolve_symlinks/2, which walks up the directory tree above the configured root and issues read_link() syscalls on arbitrary filesystem paths. An authenticated SFTP client can exploit this by sending a REALPATH request with a crafted traversal path. The server response differs depending on whether the target path exists on the host filesystem (SSH_FXP_NAME when the path resolves successfully, SSH_FX_NO_SUCH_FILE when it does not). This creates a path-existence oracle that an attacker can use to enumerate the filesystem structure outside the configured root, including the existence of sensitive files, directories, and mount points. The vulnerability leaks only the existence of paths. No file contents, credentials, or write access are obtainable through this issue alone. The information gained may assist further attacks when combined with other vulnerabilities. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routine ssh_sftpd:handle_op/4. This issue affects OTP from OTP 17.0 before OTP 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssh from 3.0.1 before 6.0.2, 5.5.2.2 and 5.2.11.9.

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6464 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6464-1                   security@debian.org     https://www.debian.org/security/                                  Aron Xu     August 25, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : erlang     CVE ID         : CVE-2026-28808 CVE-2026-28810 CVE-2026-32144 CVE-2026-32147                      CVE-2026-42789 CVE-2026-42790 CVE-2026-42791 CVE-2026-42792                      CVE-2026-47078 CVE-2026-48855 CVE-2026-48856 CVE-2026-48858                      CVE-2026-48860 CVE-2026-49759 CVE-2026-49760 CVE-2026-53422                      CVE-2026-54886 CVE-2026-54887 CVE-2026-54890 CVE-2026-54891                      CVE-2026-55737 CVE-2026-55950 CVE-2026-55952 CVE-2026-55953                      CVE-2026-58227 CVE-2026-59250 CVE-2026-59251     Debian Bug     : 1139727 1139823 1141414 1142985

    Multiple vulnerabilities were discovered in Erlang/OTP, a concurrent,     real-time, distributed functional language, which may result in denial of     service, information disclosure, authentication and certificate validation     bypass, or the execution of arbitrary code. These vulnerbilities affect a     wide range of components: TLS and certificate validation (ssl, public_key),     SSH (ssh), network clients and servers (inets, ftp, epmd, kernel),     runtime and libraries (erts, erl_interface, stdlib, megaco).

    Several of these fixes tighten checks that were previously too permissive,     and can cause configurations that worked before to stop working. The most     likely to be noticed are:

     - TLS clients using verify_peer, which is the default, now reject        certificates that carry no subjectAltName extension; the        customize_hostname_check option does not restore the old behaviour.

     - Erlang distribution over TLS with the kernel 'check_ip' option now        enforces the check that was previously a no-op, so clusters whose nodes        are not on the same subnet lose distribution connectivity until the        option is unset.

     - TLS clients that request OCSP stapling now fail the handshake when the        server provides no stapled response.

     - Clients using TLS 1.2 or earlier now abort the handshake if the server        sends an ALPN extension that the client did not advertise.

     - DNS queries made through inet_res now use randomised source ports

    For the stable distribution (trixie), these problems have been fixed in     version 1:27.3.4.1+dfsg-1+deb13u3.

    We recommend that you upgrade your erlang packages.

    For the detailed security status of erlang please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/erlang

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian 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 SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:3645-1 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-2026-49759: 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-2026-55952: 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).

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 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.

An update of the erlang package has been released.

The version of Erlang/OTP installed on the remote host is 17.0 prior to 27.3.4.14, 28.0 prior to 28.5.0.3, or 29.0 prior to 29.0.3. It is, therefore, affected by multiple vulnerabilities:

  - Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated     SFTP user to enumerate the existence of files and directories outside the configured root directory.
    (CVE-2026-53422)

  - Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in Erlang OTP ssh (ssh_sftpd module)     allows an authenticated SFTP user to render an SFTP channel permanently unresponsive. (CVE-2026-54886)

  - Improper Enforcement of Message Integrity During Transmission in a Communication Channel vulnerability in     Erlang/OTP ssl (tls_gen_connection module) allows a network-positioned attacker to inject unauthenticated     plaintext that the TLS client application later treats as authenticated server data. (CVE-2026-54891)

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.

  - Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated     SFTP user to enumerate the existence of files and directories outside the configured root directory. The     SSH_FXP_REALPATH handler in ssh_sftpd calls relate_file_name/3 with Canonicalize=false, unlike every other     SFTP operation handler. This allows .. components in the requested path to bypass the is_within_root/2     check without being resolved. The un-canonicalized path then enters resolve_symlinks/2, which walks up the     directory tree above the configured root and issues read_link() syscalls on arbitrary filesystem paths. An     authenticated SFTP client can exploit this by sending a REALPATH request with a crafted traversal path.
    The server response differs depending on whether the target path exists on the host filesystem     (SSH_FXP_NAME when the path resolves successfully, SSH_FX_NO_SUCH_FILE when it does not). This creates a     path-existence oracle that an attacker can use to enumerate the filesystem structure outside the     configured root, including the existence of sensitive files, directories, and mount points. The     vulnerability leaks only the existence of paths. No file contents, credentials, or write access are     obtainable through this issue alone. The information gained may assist further attacks when combined with     other vulnerabilities. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and     program routine ssh_sftpd:handle_op/4. This issue affects OTP from OTP 17.0 before OTP 29.0.3, OTP     28.5.0.3 and OTP 27.3.4.14, corresponding to ssh from 3.0.1 before 6.0.2, 5.5.2.2 and 5.2.11.9.
    (CVE-2026-53422)

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

ID	Name	Product	Family	Type	Severity
339216	Debian dsa-6464 : erlang - security update	Nessus	Debian Local Security Checks	Local	critical
338632	SUSE SLES15 Security Update : erlang (SUSE-SU-2026:3645-1)	Nessus	SuSE Local Security Checks	Local	critical
335097	SUSE SLES15 Security Update : erlang26 (SUSE-SU-2026:3579-1)	Nessus	SuSE Local Security Checks	Local	critical
334778	Photon OS 5.0: Erlang PHSA-2026-5.0-92-0935	Nessus	PhotonOS Local Security Checks	Local	high
325890	Erlang/OTP 17.0 < 27.3.4.14 / 28.0 < 28.5.0.3 / 29.0 < 29.0.3 Multiple Vulnerabilities	Nessus	Misc.	Local	medium
324937	Linux Distros Unpatched Vulnerability : CVE-2026-53422	Nessus	Misc.	Local	low

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CVE-2026-53422

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Tenable Plugins

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