CVE-2026-40194 | phpseclib up to 1.0.27/2.0.52/3.0.50 SSH2::get_binary_packet timing discrepancy (GHSA-r854-jrxh-36qx)

VDB-356945 · CVE-2026-40194 · GHSA-R854-JRXH-36QX PHPSECLIB UP TO 1.0.27/2.0.52/3.0.50 SSH2::GET_BINARY_PACKET TIMING DISCREPANCY HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 3.7 $0-$5k 1.68+ Summaryinfo A vulnerability, which was classified as problematic, has been found in phpseclib up to 1.0.27/2.0.52/3.0.50. The affected element is the function SSH2::get_binary_packet. The manipulation leads to timing discrepancy. This vulnerability is referenced as CVE-2026-40194. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component. Detailsinfo A vulnerability was found in phpseclib up to 1.0.27/2.0.52/3.0.50 and classified as problematic. This issue affects the function SSH2::get_binary_packet. The manipulation with an unknown input leads to a timing discrepancy vulnerability. Using CWE to declare the problem leads to CWE-208. Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not. Impacted is confidentiality. The summary by CVE is: phpseclib is a PHP secure communications library. Prior to 3.0.51, 2.0.53, and 1.0.28, phpseclib\Net\SSH2::get_binary_packet() uses PHP's != operator to compare a received SSH packet HMAC against the locally computed HMAC. != on equal-length binary strings in PHP uses memcmp(), which short-circuits on the first differing byte. This is a real variable-time comparison (CWE-208), proven by scaling benchmarks. This vulnerability is fixed in 3.0.51, 2.0.53, and 1.0.28. The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-40194 since 04/09/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1592 for this issue. Upgrading to version 1.0.28, 2.0.53 or 3.0.51 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch ffe48b6b1b1af6963327f0a5330e3aa004a194ac is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version. Productinfo Name phpseclib Version 1.0.0 1.0.1 1.0.2 1.0.3 1.0.4 1.0.5 1.0.6 1.0.7 1.0.8 1.0.9 1.0.10 1.0.11 1.0.12 1.0.13 1.0.14 1.0.15 1.0.16 1.0.17 1.0.18 1.0.19 1.0.20 1.0.21 1.0.22 1.0.23 1.0.24 1.0.25 1.0.26 1.0.27 2.0.0 2.0.1 2.0.2 2.0.3 2.0.4 2.0.5 2.0.6 2.0.7 2.0.8 2.0.9 2.0.10 2.0.11 2.0.12 2.0.13 2.0.14 2.0.15 2.0.16 2.0.17 2.0.18 2.0.19 2.0.20 2.0.21 2.0.22 2.0.23 2.0.24 2.0.25 2.0.26 2.0.27 2.0.28 2.0.29 2.0.30 2.0.31 2.0.32 2.0.33 2.0.34 2.0.35 2.0.36 2.0.37 2.0.38 2.0.39 2.0.40 2.0.41 2.0.42 2.0.43 2.0.44 2.0.45 2.0.46 2.0.47 2.0.48 2.0.49 2.0.50 2.0.51 2.0.52 3.0.0 3.0.1 3.0.2 3.0.3 3.0.4 3.0.5 3.0.6 3.0.7 3.0.8 3.0.9 3.0.10 3.0.11 3.0.12 3.0.13 3.0.14 3.0.15 3.0.16 3.0.17 3.0.18 3.0.19 3.0.20 3.0.21 3.0.22 3.0.23 3.0.24 3.0.25 3.0.26 3.0.27 3.0.28 3.0.29 3.0.30 3.0.31 3.0.32 3.0.33 3.0.34 3.0.35 3.0.36 3.0.37 3.0.38 3.0.39 3.0.40 3.0.41 3.0.42 3.0.43 3.0.44 3.0.45 3.0.46 3.0.47 3.0.48 3.0.49 3.0.50 License open-source Website Product: https://github.com/phpseclib/phpseclib/ CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 3.7 VulDB Meta Temp Score: 3.7 VulDB Base Score: 3.7 VulDB Temp Score: 3.6 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 3.7 CNA Vector (GitHub_M): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Timing discrepancy CWE: CWE-208 / CWE-203 / CWE-200 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: phpseclib 1.0.28/2.0.53/3.0.51 Patch: ffe48b6b1b1af6963327f0a5330e3aa004a194ac Timelineinfo 04/09/2026 CVE reserved 04/10/2026 +1 days Advisory disclosed 04/10/2026 +0 days VulDB entry created 04/10/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: GHSA-r854-jrxh-36qx Status: Confirmed CVE: CVE-2026-40194 (🔒) GCVE (CVE): GCVE-0-2026-40194 GCVE (VulDB): GCVE-100-356945 Entryinfo Created: 04/10/2026 23:39 Changes: 04/10/2026 23:39 (66) Complete: 🔍 Cache ID: 99:BAE:101 Discussion No comments yet. 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