SB20261001143 - Ubuntu update for phpseclib

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Main Vulnerability Database SB20261001143

SB20261001143 - Ubuntu update for phpseclib

Published: October 1, 2026

Security Bulletin ID SB20261001143
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 5
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 80% Low 20%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 5 vulnerabilities.


1) Information Exposure Through Timing Discrepancy (CVE-ID: CVE-2026-32935)

CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to observable timing discrepancy in AES-CBC unpadding when processing ciphertext in CBC mode. A remote attacker can send specially crafted ciphertext and measure response timing to disclose sensitive information.


2) Input validation error (CVE-ID: CVE-2024-27355)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.


3) Input validation error (CVE-ID: CVE-2024-27354)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input in isPrime() and randomPrime() functions. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.


4) Input validation error (CVE-ID: CVE-2023-52892)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to an error when handling some characters in Subject Alternative Name fields in TLS certificates. These fields are incorrectly allowed to have a special meaning in regular expressions (such as a + wildcard), leading to name confusion in X.509 certificate host verification.


5) Inadequate encryption strength (CVE-ID: CVE-2023-48795)

CWE-ID: CWE-326 - Inadequate Encryption Strength

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to incorrect implementation of the SSH Binary Packet Protocol (BPP), which mishandles the handshake phase and the use of sequence numbers. A remote attacker can perform MitM attack and delete the SSH2_MSG_EXT_INFO message sent before authentication starts, allowing the attacker to disable a subset of the keystroke timing obfuscation features introduced in OpenSSH 9.5.

The vulnerability was dubbed "Terrapin attack" and it affects both client and server implementations.


Remediation

Install update from vendor's website.

References