Jakub Witczak

21 exploits Active since Feb 2025
CVE-2026-48859 WRITEUP MEDIUM WRITEUP
SSH server timing side-channel in ssh_auth:check_password/3 allows unauthenticated username enumeration
Observable Timing Discrepancy vulnerability in Erlang/OTP ssh (ssh_auth, ssh_options modules) allows unauthenticated remote username enumeration via timing side-channel in password authentication. When the SSH daemon is configured with the user_passwords or password option, ssh_auth:check_password/3 performs a PBKDF2-SHA256 computation with 600,000 iterations (~300ms) for valid usernames, but returns immediately (~0ms) for invalid usernames via the ssh_options:get_password_option/2 path. This timing difference is detectable in a single authentication attempt and allows an unauthenticated attacker to distinguish valid from invalid usernames. The user_passwords and password options are documented as intended for test purposes; the recommended alternative is pwdfun, which is not affected by this vulnerability. This vulnerability is associated with program files lib/ssh/src/ssh_auth.erl and lib/ssh/src/ssh_options.erl. This issue affects OTP from OTP 29.0 before 29.0.2 corresponding to ssh from 6.0 before 6.0.1.
CVSS 5.3
CVE-2026-42791 WRITEUP LOW WRITEUP
OCSP responder certificate validity period not checked in public_key
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid. This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate. This issue affects OTP from OTP 27.0 before OTP 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.16 before 1.17.1.3, 1.20.3.1, and 1.21.1.
CVSS 3.7
CVE-2026-42791 WRITEUP LOW WRITEUP
OCSP responder certificate validity period not checked in public_key
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid. This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate. This issue affects OTP from OTP 27.0 before OTP 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.16 before 1.17.1.3, 1.20.3.1, and 1.21.1.
CVSS 3.7
CVE-2025-32433 WRITEUP CRITICAL WRITEUP
Erlang OTP Pre-Auth RCE Scanner and Exploit
Erlang/OTP is a set of libraries for the Erlang programming language. Prior to versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20, a SSH server may allow an attacker to perform unauthenticated remote code execution (RCE). By exploiting a flaw in SSH protocol message handling, a malicious actor could gain unauthorized access to affected systems and execute arbitrary commands without valid credentials. This issue is patched in versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20. A temporary workaround involves disabling the SSH server or to prevent access via firewall rules.
CVSS 10.0
CVE-2025-32433 WRITEUP CRITICAL WRITEUP
Erlang OTP Pre-Auth RCE Scanner and Exploit
Erlang/OTP is a set of libraries for the Erlang programming language. Prior to versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20, a SSH server may allow an attacker to perform unauthenticated remote code execution (RCE). By exploiting a flaw in SSH protocol message handling, a malicious actor could gain unauthorized access to affected systems and execute arbitrary commands without valid credentials. This issue is patched in versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20. A temporary workaround involves disabling the SSH server or to prevent access via firewall rules.
CVSS 10.0
CVE-2025-32433 WRITEUP CRITICAL WRITEUP
Erlang OTP Pre-Auth RCE Scanner and Exploit
Erlang/OTP is a set of libraries for the Erlang programming language. Prior to versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20, a SSH server may allow an attacker to perform unauthenticated remote code execution (RCE). By exploiting a flaw in SSH protocol message handling, a malicious actor could gain unauthorized access to affected systems and execute arbitrary commands without valid credentials. This issue is patched in versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20. A temporary workaround involves disabling the SSH server or to prevent access via firewall rules.
CVSS 10.0
CVE-2025-48038 WRITEUP MEDIUM WRITEUP
Erlang OTP - Resource Leak Exposure
Allocation of Resources Without Limits or Throttling vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Resource Leak Exposure. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2025-48039 WRITEUP MEDIUM WRITEUP
Erlang OTP <28.0.3 - Excessive Allocation
Allocation of Resources Without Limits or Throttling vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Resource Leak Exposure. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2025-48040 WRITEUP MEDIUM WRITEUP
Erlang OTP <28.0.3 - Uncontrolled Resource Consumption
Uncontrolled Resource Consumption vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Flooding. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2025-48041 WRITEUP HIGH WRITEUP
Erlang/OTP 17.0-28.0.3, 27.3.4.3, 26.2.5.15 - Uncontrolled Resource Consumption in SSH SFTP Module
Allocation of Resources Without Limits or Throttling vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Flooding. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2026-23942 WRITEUP MEDIUM WRITEUP
Erlang OTP ssh_sftpd - Path Traversal
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP (ssh_sftpd module) allows Path Traversal. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routines ssh_sftpd:is_within_root/2. The SFTP server uses string prefix matching via lists:prefix/2 rather than proper path component validation when checking if a path is within the configured root directory. This allows authenticated users to access sibling directories that share a common name prefix with the configured root directory. For example, if root is set to /home/user1, paths like /home/user10 or /home/user1_backup would incorrectly be considered within the root. This issue affects OTP from OTP 17.0 until OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.
CVSS 5.4
CVE-2026-23942 WRITEUP MEDIUM WRITEUP
Erlang OTP ssh_sftpd - Path Traversal
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP (ssh_sftpd module) allows Path Traversal. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routines ssh_sftpd:is_within_root/2. The SFTP server uses string prefix matching via lists:prefix/2 rather than proper path component validation when checking if a path is within the configured root directory. This allows authenticated users to access sibling directories that share a common name prefix with the configured root directory. For example, if root is set to /home/user1, paths like /home/user10 or /home/user1_backup would incorrectly be considered within the root. This issue affects OTP from OTP 17.0 until OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.
CVSS 5.4
CVE-2026-32144 WRITEUP HIGH WRITEUP
OCSP designated-responder authorization bypass via missing signature verification
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows OCSP designated-responder authorization bypass via missing signature verification. The OCSP response validation in public_key:pkix_ocsp_validate/5 does not verify that a CA-designated responder certificate was cryptographically signed by the issuing CA. Instead, it only checks that the responder certificate's issuer name matches the CA's subject name and that the certificate has the OCSPSigning extended key usage. An attacker who can intercept or control OCSP responses can create a self-signed certificate with a matching issuer name and the OCSPSigning EKU, and use it to forge OCSP responses that mark revoked certificates as valid. This affects SSL/TLS clients using OCSP stapling, which may accept connections to servers with revoked certificates, potentially transmitting sensitive data to compromised servers. Applications using the public_key:pkix_ocsp_validate/5 API directly are also affected, with impact depending on usage context. This vulnerability is associated with program files lib/public_key/src/pubkey_ocsp.erl and program routines pubkey_ocsp:is_authorized_responder/3. This issue affects OTP from OTP 27.0 until OTP 28.4.2 and 27.3.4.10 corresponding to public_key from 1.16 until 1.20.3 and 1.17.1.2, and ssl from 11.2 until 11.5.4 and 11.2.12.7.
CVSS 7.4
CVE-2026-32144 WRITEUP HIGH WRITEUP
OCSP designated-responder authorization bypass via missing signature verification
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows OCSP designated-responder authorization bypass via missing signature verification. The OCSP response validation in public_key:pkix_ocsp_validate/5 does not verify that a CA-designated responder certificate was cryptographically signed by the issuing CA. Instead, it only checks that the responder certificate's issuer name matches the CA's subject name and that the certificate has the OCSPSigning extended key usage. An attacker who can intercept or control OCSP responses can create a self-signed certificate with a matching issuer name and the OCSPSigning EKU, and use it to forge OCSP responses that mark revoked certificates as valid. This affects SSL/TLS clients using OCSP stapling, which may accept connections to servers with revoked certificates, potentially transmitting sensitive data to compromised servers. Applications using the public_key:pkix_ocsp_validate/5 API directly are also affected, with impact depending on usage context. This vulnerability is associated with program files lib/public_key/src/pubkey_ocsp.erl and program routines pubkey_ocsp:is_authorized_responder/3. This issue affects OTP from OTP 27.0 until OTP 28.4.2 and 27.3.4.10 corresponding to public_key from 1.16 until 1.20.3 and 1.17.1.2, and ssl from 11.2 until 11.5.4 and 11.2.12.7.
CVSS 7.4
CVE-2026-23942 WRITEUP MEDIUM WRITEUP
Erlang OTP ssh_sftpd - Path Traversal
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP (ssh_sftpd module) allows Path Traversal. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routines ssh_sftpd:is_within_root/2. The SFTP server uses string prefix matching via lists:prefix/2 rather than proper path component validation when checking if a path is within the configured root directory. This allows authenticated users to access sibling directories that share a common name prefix with the configured root directory. For example, if root is set to /home/user1, paths like /home/user10 or /home/user1_backup would incorrectly be considered within the root. This issue affects OTP from OTP 17.0 until OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.
CVSS 5.4
CVE-2025-26618 WRITEUP HIGH WRITEUP
Erlang/OTP 25.3.2.18-27.2.3 - Authenticated Denial of Service via SFTP Packet Size Mismatch
Erlang is a programming language and runtime system for building massively scalable soft real-time systems with requirements on high availability. OTP is a set of Erlang libraries, which consists of the Erlang runtime system, a number of ready-to-use components mainly written in Erlang. Packet size is not verified properly for SFTP packets. As a result when multiple SSH packets (conforming to max SSH packet size) are received by ssh, they might be combined into an SFTP packet which will exceed the max allowed packet size and potentially cause large amount of memory to be allocated. Note that situation described above can only happen for successfully authenticated users after completing the SSH handshake. This issue has been patched in OTP versions 27.2.4, 26.2.5.9, and 25.3.2.18. There are no known workarounds for this vulnerability.
CVE-2025-46712 WRITEUP LOW WRITEUP
Erlang/OTP <27.3.4, <26.2.5.12, <25.3.2.21 - Man-in-the-Middle
Erlang/OTP is a set of libraries for the Erlang programming language. In versions prior to OTP-27.3.4 (for OTP-27), OTP-26.2.5.12 (for OTP-26), and OTP-25.3.2.21 (for OTP-25), Erlang/OTP SSH fails to enforce strict KEX handshake hardening measures by allowing optional messages to be exchanged. This allows a Man-in-the-Middle attacker to inject these messages in a connection during the handshake. This issue has been patched in versions OTP-27.3.4 (for OTP-27), OTP-26.2.5.12 (for OTP-26), and OTP-25.3.2.21 (for OTP-25).
CVSS 3.7
CVE-2025-48038 WRITEUP MEDIUM WRITEUP
Erlang OTP - Resource Leak Exposure
Allocation of Resources Without Limits or Throttling vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Resource Leak Exposure. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2025-48039 WRITEUP MEDIUM WRITEUP
Erlang OTP <28.0.3 - Excessive Allocation
Allocation of Resources Without Limits or Throttling vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Resource Leak Exposure. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2025-48040 WRITEUP MEDIUM WRITEUP
Erlang OTP <28.0.3 - Uncontrolled Resource Consumption
Uncontrolled Resource Consumption vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Flooding. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.
CVE-2025-48041 WRITEUP HIGH WRITEUP
Erlang/OTP 17.0-28.0.3, 27.3.4.3, 26.2.5.15 - Uncontrolled Resource Consumption in SSH SFTP Module
Allocation of Resources Without Limits or Throttling vulnerability in Erlang OTP ssh (ssh_sftp modules) allows Excessive Allocation, Flooding. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 until OTP 28.0.3, OTP 27.3.4.3 and 26.2.5.15 corresponding to ssh from 3.0.1 until 5.3.3, 5.2.11.3 and 5.1.4.12.